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Populaire Trigonométrie >

tan^2(x)-4sin(x)+4=0

Solution

tan^{2} (x) - 4 sin (x) + 4 = 0

Solution

Aucune solution pour x \in R

étapes des solutions

tan^{2} (x) - 4 sin (x) + 4 = 0

Ajouter

4 sin (x)

aux deux côtés

tan^{2} (x) + 4 = 4 sin (x)

Mettre les deux côtés au carré

(tan^{2} (x) + 4)^{2} = (4 sin (x))^{2}

Soustraire

(4 sin (x))^{2}

des deux côtés

(tan^{2} (x) + 4)^{2} - 16 sin^{2} (x) = 0

Récrire en utilisant des identités trigonométriques

(4 + tan^{2} (x))^{2} - 16 sin^{2} (x)

Utiliser l'identité trigonométrique de base:

tan (x) = \frac{sin ( x )}{cos ( x )}

= (4 + (\frac{sin ( x )}{cos ( x )})^{2})^{2} - 16 sin^{2} (x)

Appliquer la règle de l'exposant:

(\frac{a}{b})^{c} = \frac{a ^{c}}{b ^{c}}

= (4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )})^{2} - 16 sin^{2} (x)

(4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )})^{2} - 16 sin^{2} (x) = 0

Factoriser

(4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )})^{2} - 16 sin^{2} (x) : (4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} + 4 sin (x)) (4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} - 4 sin (x))

(4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )})^{2} - 16 sin^{2} (x)

Récrire

16 sin^{2} (x)

comme

(2^{2} sin (x))^{2}

16 sin^{2} (x)

Appliquer la règle de l'exposant:

a^{b c} = (a^{b})^{c}

16 = (2^{2})^{2}

= (2^{2})^{2} sin^{2} (x)

Appliquer la règle de l'exposant:

a^{m} b^{m} = (ab)^{m}

(2^{2})^{2} sin^{2} (x) = (2^{2} sin (x))^{2}

= (2^{2} sin (x))^{2}

= (4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )})^{2} - (2^{2} sin (x))^{2}

Appliquer la formule de différence de deux carrés :

x^{2} - y^{2} = (x + y) (x - y)

(4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )})^{2} - (2^{2} sin (x))^{2} = ((4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )}) + 2^{2} sin (x)) ((4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )}) - 2^{2} sin (x))

= ((4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )}) + 2^{2} sin (x)) ((4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )}) - 2^{2} sin (x))

Redéfinir

= (\frac{sin ^{2} ( x )}{cos ^{2} ( x )} + 4 sin (x) + 4) (\frac{sin ^{2} ( x )}{cos ^{2} ( x )} - 4 sin (x) + 4)

(4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} + 4 sin (x)) (4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} - 4 sin (x)) = 0

En solutionnant chaque partie séparément

4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} + 4 sin (x) = 0 or 4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} - 4 sin (x) = 0

4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} + 4 sin (x) = 0 :

Aucune solution

4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} + 4 sin (x) = 0

Simplifier

4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} + 4 sin (x) : \frac{4 cos ^{2} ( x ) + sin ^{2} ( x ) + 4 cos ^{2} ( x ) sin ( x )}{cos ^{2} ( x )}

4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} + 4 sin (x)

Convertir un élément en fraction:

4 = \frac{4 cos ^{2} ( x )}{cos ^{2} ( x )}, 4 sin (x) = \frac{4 sin ( x ) cos ^{2} ( x )}{cos ^{2} ( x )}

= \frac{4 cos ^{2} ( x )}{cos ^{2} ( x )} + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} + \frac{4 sin ( x ) cos ^{2} ( x )}{cos ^{2} ( x )}

Puisque les dénominateurs sont égaux, combiner les fractions:

\frac{a}{c} \pm \frac{b}{c} = \frac{a \pm b}{c}

= \frac{4 cos ^{2} ( x ) + sin ^{2} ( x ) + 4 sin ( x ) cos ^{2} ( x )}{cos ^{2} ( x )}

\frac{4 cos ^{2} ( x ) + sin ^{2} ( x ) + 4 cos ^{2} ( x ) sin ( x )}{cos ^{2} ( x )} = 0

\frac{f ( x )}{g ( x )} = 0 \Rightarrow f (x) = 0

4 cos^{2} (x) + sin^{2} (x) + 4 cos^{2} (x) sin (x) = 0

Récrire en utilisant des identités trigonométriques

sin^{2} (x) + 4 cos^{2} (x) + 4 cos^{2} (x) sin (x)

Utiliser l'identité hyperbolique:

cos^{2} (x) + sin^{2} (x) = 1

cos^{2} (x) = 1 - sin^{2} (x)

= sin^{2} (x) + 4 (1 - sin^{2} (x)) + 4 (1 - sin^{2} (x)) sin (x)

Simplifier

sin^{2} (x) + 4 (1 - sin^{2} (x)) + 4 (1 - sin^{2} (x)) sin (x) : - 3 sin^{2} (x) + 4 sin (x) - 4 sin^{3} (x) + 4

sin^{2} (x) + 4 (1 - sin^{2} (x)) + 4 (1 - sin^{2} (x)) sin (x)

= sin^{2} (x) + 4 (1 - sin^{2} (x)) + 4 sin (x) (1 - sin^{2} (x))

Développer

4 (1 - sin^{2} (x)) : 4 - 4 sin^{2} (x)

4 (1 - sin^{2} (x))

Appliquer la loi de la distribution:

a (b - c) = ab - a c

a = 4, b = 1, c = sin^{2} (x)

= 4 \cdot 1 - 4 sin^{2} (x)

Multiplier les nombres :

4 \cdot 1 = 4

= 4 - 4 sin^{2} (x)

= sin^{2} (x) + 4 - 4 sin^{2} (x) + 4 (1 - sin^{2} (x)) sin (x)

Développer

4 sin (x) (1 - sin^{2} (x)) : 4 sin (x) - 4 sin^{3} (x)

4 sin (x) (1 - sin^{2} (x))

Appliquer la loi de la distribution:

a (b - c) = ab - a c

a = 4 sin (x), b = 1, c = sin^{2} (x)

= 4 sin (x) \cdot 1 - 4 sin (x) sin^{2} (x)

= 4 \cdot 1 \cdot sin (x) - 4 sin^{2} (x) sin (x)

Simplifier

4 \cdot 1 \cdot sin (x) - 4 sin^{2} (x) sin (x) : 4 sin (x) - 4 sin^{3} (x)

4 \cdot 1 \cdot sin (x) - 4 sin^{2} (x) sin (x)

4 \cdot 1 \cdot sin (x) = 4 sin (x)

4 \cdot 1 \cdot sin (x)

Multiplier les nombres :

4 \cdot 1 = 4

= 4 sin (x)

4 sin^{2} (x) sin (x) = 4 sin^{3} (x)

4 sin^{2} (x) sin (x)

Appliquer la règle de l'exposant:

a^{b} \cdot a^{c} = a^{b + c}

sin^{2} (x) sin (x) = sin^{2 + 1} (x)

= 4 sin^{2 + 1} (x)

Additionner les nombres :

2 + 1 = 3

= 4 sin^{3} (x)

= 4 sin (x) - 4 sin^{3} (x)

= 4 sin (x) - 4 sin^{3} (x)

= sin^{2} (x) + 4 - 4 sin^{2} (x) + 4 sin (x) - 4 sin^{3} (x)

Simplifier

sin^{2} (x) + 4 - 4 sin^{2} (x) + 4 sin (x) - 4 sin^{3} (x) : - 3 sin^{2} (x) + 4 sin (x) - 4 sin^{3} (x) + 4

sin^{2} (x) + 4 - 4 sin^{2} (x) + 4 sin (x) - 4 sin^{3} (x)

Grouper comme termes

= sin^{2} (x) - 4 sin^{2} (x) + 4 sin (x) - 4 sin^{3} (x) + 4

Additionner les éléments similaires :

sin^{2} (x) - 4 sin^{2} (x) = - 3 sin^{2} (x)

= - 3 sin^{2} (x) + 4 sin (x) - 4 sin^{3} (x) + 4

= - 3 sin^{2} (x) + 4 sin (x) - 4 sin^{3} (x) + 4

= - 3 sin^{2} (x) + 4 sin (x) - 4 sin^{3} (x) + 4

4 - 3 sin^{2} (x) + 4 sin (x) - 4 sin^{3} (x) = 0

Résoudre par substitution

4 - 3 sin^{2} (x) + 4 sin (x) - 4 sin^{3} (x) = 0

Soit :

sin (x) = u

4 - 3 u^{2} + 4 u - 4 u^{3} = 0

4 - 3 u^{2} + 4 u - 4 u^{3} = 0 : u \approx 1.06659 \dots

4 - 3 u^{2} + 4 u - 4 u^{3} = 0

Ecrire sous la forme standard

a_{n} x^{n} + \dots + a_{1} x + a_{0} = 0

- 4 u^{3} - 3 u^{2} + 4 u + 4 = 0

Trouver une solution pour

- 4 u^{3} - 3 u^{2} + 4 u + 4 = 0

par la méthode de Newton-Raphson:

u \approx 1.06659 \dots

- 4 u^{3} - 3 u^{2} + 4 u + 4 = 0

Définition de l'approximation de Newton-Raphson

f (u) = - 4 u^{3} - 3 u^{2} + 4 u + 4

Trouver

f^{^{'}} (u) : - 12 u^{2} - 6 u + 4

\frac{d}{d u} (- 4 u^{3} - 3 u^{2} + 4 u + 4)

Appliquer la règle de l'addition/soustraction:

(f \pm g)^{'} = f^{'} \pm g^{'}

= - \frac{d}{d u} (4 u^{3}) - \frac{d}{d u} (3 u^{2}) + \frac{d}{d u} (4 u) + \frac{d}{d u} (4)

\frac{d}{d u} (4 u^{3}) = 12 u^{2}

\frac{d}{d u} (4 u^{3})

Retirer la constante:

(a \cdot f)^{'} = a \cdot f^{'}

= 4 \frac{d}{d u} (u^{3})

Appliquer la règle de la puissance:

\frac{d}{d x} (x^{a}) = a \cdot x^{a - 1}

= 4 \cdot 3 u^{3 - 1}

Simplifier

= 12 u^{2}

\frac{d}{d u} (3 u^{2}) = 6 u

\frac{d}{d u} (3 u^{2})

Retirer la constante:

(a \cdot f)^{'} = a \cdot f^{'}

= 3 \frac{d}{d u} (u^{2})

Appliquer la règle de la puissance:

\frac{d}{d x} (x^{a}) = a \cdot x^{a - 1}

= 3 \cdot 2 u^{2 - 1}

Simplifier

= 6 u

\frac{d}{d u} (4 u) = 4

\frac{d}{d u} (4 u)

Retirer la constante:

(a \cdot f)^{'} = a \cdot f^{'}

= 4 \frac{d u}{d u}

Appliquer la dérivée commune:

\frac{d u}{d u} = 1

= 4 \cdot 1

Simplifier

= 4

\frac{d}{d u} (4) = 0

\frac{d}{d u} (4)

Dérivée d'une constante:

\frac{d}{d x} (a) = 0

= 0

= - 12 u^{2} - 6 u + 4 + 0

Simplifier

= - 12 u^{2} - 6 u + 4

Soit

u_{0} = 1

Calculer

u_{n + 1}

jusqu'à

Δ u_{n + 1} < 0.000001

u_{1} = 1.07142 \dots : Δ u_{1} = 0.07142 \dots

f (u_{0}) = - 4 \cdot 1^{3} - 3 \cdot 1^{2} + 4 \cdot 1 + 4 = 1

f^{^{'}} (u_{0}) = - 12 \cdot 1^{2} - 6 \cdot 1 + 4 = - 14

u_{1} = 1.07142 \dots

Δ u_{1} = ∣ 1.07142 \dots - 1 ∣ = 0.07142 \dots

Δ u_{1} = 0.07142 \dots

u_{2} = 1.06661 \dots : Δ u_{2} = 0.00481 \dots

f (u_{1}) = - 4 \cdot 1.07142 \dots^{3} - 3 \cdot 1.07142 \dots^{2} + 4 \cdot 1.07142 \dots + 4 = - 0.07798 \dots

f^{^{'}} (u_{1}) = - 12 \cdot 1.07142 \dots^{2} - 6 \cdot 1.07142 \dots + 4 = - 16.20408 \dots

u_{2} = 1.06661 \dots

Δ u_{2} = ∣ 1.06661 \dots - 1.07142 \dots ∣ = 0.00481 \dots

Δ u_{2} = 0.00481 \dots

u_{3} = 1.06659 \dots : Δ u_{3} = 0.00002 \dots

f (u_{2}) = - 4 \cdot 1.06661 \dots^{3} - 3 \cdot 1.06661 \dots^{2} + 4 \cdot 1.06661 \dots + 4 = - 0.00036 \dots

f^{^{'}} (u_{2}) = - 12 \cdot 1.06661 \dots^{2} - 6 \cdot 1.06661 \dots + 4 = - 16.05172 \dots

u_{3} = 1.06659 \dots

Δ u_{3} = ∣ 1.06659 \dots - 1.06661 \dots ∣ = 0.00002 \dots

Δ u_{3} = 0.00002 \dots

u_{4} = 1.06659 \dots : Δ u_{4} = 5.14172 E - 10

f (u_{3}) = - 4 \cdot 1.06659 \dots^{3} - 3 \cdot 1.06659 \dots^{2} + 4 \cdot 1.06659 \dots + 4 = - 8.25297 E - 9

f^{^{'}} (u_{3}) = - 12 \cdot 1.06659 \dots^{2} - 6 \cdot 1.06659 \dots + 4 = - 16.05100 \dots

u_{4} = 1.06659 \dots

Δ u_{4} = ∣ 1.06659 \dots - 1.06659 \dots ∣ = 5.14172 E - 10

Δ u_{4} = 5.14172 E - 10

u \approx 1.06659 \dots

Appliquer une division longue:

\frac{- 4 u ^{3} - 3 u ^{2} + 4 u + 4}{u - 1.06659 \dots} = - 4 u^{2} - 7.26637 \dots u - 3.75025 \dots

- 4 u^{2} - 7.26637 \dots u - 3.75025 \dots \approx 0

Trouver une solution pour

- 4 u^{2} - 7.26637 \dots u - 3.75025 \dots = 0

par la méthode de Newton-Raphson:

Aucune solution pour

u \in R

- 4 u^{2} - 7.26637 \dots u - 3.75025 \dots = 0

Définition de l'approximation de Newton-Raphson

f (u) = - 4 u^{2} - 7.26637 \dots u - 3.75025 \dots

Trouver

f^{^{'}} (u) : - 8 u - 7.26637 \dots

\frac{d}{d u} (- 4 u^{2} - 7.26637 \dots u - 3.75025 \dots)

Appliquer la règle de l'addition/soustraction:

(f \pm g)^{'} = f^{'} \pm g^{'}

= - \frac{d}{d u} (4 u^{2}) - \frac{d}{d u} (7.26637 \dots u) - \frac{d}{d u} (3.75025 \dots)

\frac{d}{d u} (4 u^{2}) = 8 u

\frac{d}{d u} (4 u^{2})

Retirer la constante:

(a \cdot f)^{'} = a \cdot f^{'}

= 4 \frac{d}{d u} (u^{2})

Appliquer la règle de la puissance:

\frac{d}{d x} (x^{a}) = a \cdot x^{a - 1}

= 4 \cdot 2 u^{2 - 1}

Simplifier

= 8 u

\frac{d}{d u} (7.26637 \dots u) = 7.26637 \dots

\frac{d}{d u} (7.26637 \dots u)

Retirer la constante:

(a \cdot f)^{'} = a \cdot f^{'}

= 7.26637 \dots \frac{d u}{d u}

Appliquer la dérivée commune:

\frac{d u}{d u} = 1

= 7.26637 \dots \cdot 1

Simplifier

= 7.26637 \dots

\frac{d}{d u} (3.75025 \dots) = 0

\frac{d}{d u} (3.75025 \dots)

Dérivée d'une constante:

\frac{d}{d x} (a) = 0

= 0

= - 8 u - 7.26637 \dots - 0

Simplifier

= - 8 u - 7.26637 \dots

Soit

u_{0} = - 1

Calculer

u_{n + 1}

jusqu'à

Δ u_{n + 1} < 0.000001

u_{1} = - 0.34041 \dots : Δ u_{1} = 0.65958 \dots

f (u_{0}) = - 4 (- 1)^{2} - 7.26637 \dots (- 1) - 3.75025 \dots = - 0.48388 \dots

f^{^{'}} (u_{0}) = - 8 (- 1) - 7.26637 \dots = 0.73362 \dots

u_{1} = - 0.34041 \dots

Δ u_{1} = ∣ - 0.34041 \dots - (- 1) ∣ = 0.65958 \dots

Δ u_{1} = 0.65958 \dots

u_{2} = - 0.72346 \dots : Δ u_{2} = 0.38304 \dots

f (u_{1}) = - 4 (- 0.34041 \dots)^{2} - 7.26637 \dots (- 0.34041 \dots) - 3.75025 \dots = - 1.74019 \dots

f^{^{'}} (u_{1}) = - 8 (- 0.34041 \dots) - 7.26637 \dots = - 4.54302 \dots

u_{2} = - 0.72346 \dots

Δ u_{2} = ∣ - 0.72346 \dots - (- 0.34041 \dots) ∣ = 0.38304 \dots

Δ u_{2} = 0.38304 \dots

u_{3} = - 1.12038 \dots : Δ u_{3} = 0.39691 \dots

f (u_{2}) = - 4 (- 0.72346 \dots)^{2} - 7.26637 \dots (- 0.72346 \dots) - 3.75025 \dots = - 0.58690 \dots

f^{^{'}} (u_{2}) = - 8 (- 0.72346 \dots) - 7.26637 \dots = - 1.47865 \dots

u_{3} = - 1.12038 \dots

Δ u_{3} = ∣ - 1.12038 \dots - (- 0.72346 \dots) ∣ = 0.39691 \dots

Δ u_{3} = 0.39691 \dots

u_{4} = - 0.74896 \dots : Δ u_{4} = 0.37141 \dots

f (u_{3}) = - 4 (- 1.12038 \dots)^{2} - 7.26637 \dots (- 1.12038 \dots) - 3.75025 \dots = - 0.63017 \dots

f^{^{'}} (u_{3}) = - 8 (- 1.12038 \dots) - 7.26637 \dots = 1.69668 \dots

u_{4} = - 0.74896 \dots

Δ u_{4} = ∣ - 0.74896 \dots - (- 1.12038 \dots) ∣ = 0.37141 \dots

Δ u_{4} = 0.37141 \dots

u_{5} = - 1.18187 \dots : Δ u_{5} = 0.43290 \dots

f (u_{4}) = - 4 (- 0.74896 \dots)^{2} - 7.26637 \dots (- 0.74896 \dots) - 3.75025 \dots = - 0.55179 \dots

f^{^{'}} (u_{4}) = - 8 (- 0.74896 \dots) - 7.26637 \dots = - 1.27462 \dots

u_{5} = - 1.18187 \dots

Δ u_{5} = ∣ - 1.18187 \dots - (- 0.74896 \dots) ∣ = 0.43290 \dots

Δ u_{5} = 0.43290 \dots

u_{6} = - 0.83936 \dots : Δ u_{6} = 0.34251 \dots

f (u_{5}) = - 4 (- 1.18187 \dots)^{2} - 7.26637 \dots (- 1.18187 \dots) - 3.75025 \dots = - 0.74962 \dots

f^{^{'}} (u_{5}) = - 8 (- 1.18187 \dots) - 7.26637 \dots = 2.18860 \dots

u_{6} = - 0.83936 \dots

Δ u_{6} = ∣ - 0.83936 \dots - (- 1.18187 \dots) ∣ = 0.34251 \dots

Δ u_{6} = 0.34251 \dots

u_{7} = - 1.69025 \dots : Δ u_{7} = 0.85089 \dots

f (u_{6}) = - 4 (- 0.83936 \dots)^{2} - 7.26637 \dots (- 0.83936 \dots) - 3.75025 \dots = - 0.46925 \dots

f^{^{'}} (u_{6}) = - 8 (- 0.83936 \dots) - 7.26637 \dots = - 0.55149 \dots

u_{7} = - 1.69025 \dots

Δ u_{7} = ∣ - 1.69025 \dots - (- 0.83936 \dots) ∣ = 0.85089 \dots

Δ u_{7} = 0.85089 \dots

u_{8} = - 1.22729 \dots : Δ u_{8} = 0.46295 \dots

f (u_{7}) = - 4 (- 1.69025 \dots)^{2} - 7.26637 \dots (- 1.69025 \dots) - 3.75025 \dots = - 2.89606 \dots

f^{^{'}} (u_{7}) = - 8 (- 1.69025 \dots) - 7.26637 \dots = 6.25564 \dots

u_{8} = - 1.22729 \dots

Δ u_{8} = ∣ - 1.22729 \dots - (- 1.69025 \dots) ∣ = 0.46295 \dots

Δ u_{8} = 0.46295 \dots

u_{9} = - 0.89136 \dots : Δ u_{9} = 0.33593 \dots

f (u_{8}) = - 4 (- 1.22729 \dots)^{2} - 7.26637 \dots (- 1.22729 \dots) - 3.75025 \dots = - 0.85730 \dots

f^{^{'}} (u_{8}) = - 8 (- 1.22729 \dots) - 7.26637 \dots = 2.55202 \dots

u_{9} = - 0.89136 \dots

Δ u_{9} = ∣ - 0.89136 \dots - (- 1.22729 \dots) ∣ = 0.33593 \dots

Δ u_{9} = 0.33593 \dots

u_{10} = - 4.22467 \dots : Δ u_{10} = 3.33330 \dots

f (u_{9}) = - 4 (- 0.89136 \dots)^{2} - 7.26637 \dots (- 0.89136 \dots) - 3.75025 \dots = - 0.45139 \dots

f^{^{'}} (u_{9}) = - 8 (- 0.89136 \dots) - 7.26637 \dots = - 0.13541 \dots

u_{10} = - 4.22467 \dots

Δ u_{10} = ∣ - 4.22467 \dots - (- 0.89136 \dots) ∣ = 3.33330 \dots

Δ u_{10} = 3.33330 \dots

Impossible de trouver une solution

La solution est

u \approx 1.06659 \dots

Remplacer

u = sin (x)

sin (x) \approx 1.06659 \dots

sin (x) \approx 1.06659 \dots

sin (x) = 1.06659 \dots :

Aucune solution

sin (x) = 1.06659 \dots

- 1 \leq sin (x) \leq 1

Aucune solution

Combiner toutes les solutions

Aucune solution

4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} - 4 sin (x) = 0 :

Aucune solution

4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} - 4 sin (x) = 0

Simplifier

4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} - 4 sin (x) : \frac{4 cos ^{2} ( x ) + sin ^{2} ( x ) - 4 cos ^{2} ( x ) sin ( x )}{cos ^{2} ( x )}

4 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} - 4 sin (x)

Convertir un élément en fraction:

4 = \frac{4 cos ^{2} ( x )}{cos ^{2} ( x )}, 4 sin (x) = \frac{4 sin ( x ) cos ^{2} ( x )}{cos ^{2} ( x )}

= \frac{4 cos ^{2} ( x )}{cos ^{2} ( x )} + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} - \frac{4 sin ( x ) cos ^{2} ( x )}{cos ^{2} ( x )}

Puisque les dénominateurs sont égaux, combiner les fractions:

\frac{a}{c} \pm \frac{b}{c} = \frac{a \pm b}{c}

= \frac{4 cos ^{2} ( x ) + sin ^{2} ( x ) - 4 sin ( x ) cos ^{2} ( x )}{cos ^{2} ( x )}

\frac{4 cos ^{2} ( x ) + sin ^{2} ( x ) - 4 cos ^{2} ( x ) sin ( x )}{cos ^{2} ( x )} = 0

\frac{f ( x )}{g ( x )} = 0 \Rightarrow f (x) = 0

4 cos^{2} (x) + sin^{2} (x) - 4 cos^{2} (x) sin (x) = 0

Récrire en utilisant des identités trigonométriques

sin^{2} (x) + 4 cos^{2} (x) - 4 cos^{2} (x) sin (x)

Utiliser l'identité hyperbolique:

cos^{2} (x) + sin^{2} (x) = 1

cos^{2} (x) = 1 - sin^{2} (x)

= sin^{2} (x) + 4 (1 - sin^{2} (x)) - 4 (1 - sin^{2} (x)) sin (x)

Simplifier

sin^{2} (x) + 4 (1 - sin^{2} (x)) - 4 (1 - sin^{2} (x)) sin (x) : - 3 sin^{2} (x) - 4 sin (x) + 4 sin^{3} (x) + 4

sin^{2} (x) + 4 (1 - sin^{2} (x)) - 4 (1 - sin^{2} (x)) sin (x)

= sin^{2} (x) + 4 (1 - sin^{2} (x)) - 4 sin (x) (1 - sin^{2} (x))

Développer

4 (1 - sin^{2} (x)) : 4 - 4 sin^{2} (x)

4 (1 - sin^{2} (x))

Appliquer la loi de la distribution:

a (b - c) = ab - a c

a = 4, b = 1, c = sin^{2} (x)

= 4 \cdot 1 - 4 sin^{2} (x)

Multiplier les nombres :

4 \cdot 1 = 4

= 4 - 4 sin^{2} (x)

= sin^{2} (x) + 4 - 4 sin^{2} (x) - 4 (1 - sin^{2} (x)) sin (x)

Développer

- 4 sin (x) (1 - sin^{2} (x)) : - 4 sin (x) + 4 sin^{3} (x)

- 4 sin (x) (1 - sin^{2} (x))

Appliquer la loi de la distribution:

a (b - c) = ab - a c

a = - 4 sin (x), b = 1, c = sin^{2} (x)

= - 4 sin (x) \cdot 1 - (- 4 sin (x)) sin^{2} (x)

Appliquer les règles des moins et des plus

- (- a) = a

= - 4 \cdot 1 \cdot sin (x) + 4 sin^{2} (x) sin (x)

Simplifier

- 4 \cdot 1 \cdot sin (x) + 4 sin^{2} (x) sin (x) : - 4 sin (x) + 4 sin^{3} (x)

- 4 \cdot 1 \cdot sin (x) + 4 sin^{2} (x) sin (x)

4 \cdot 1 \cdot sin (x) = 4 sin (x)

4 \cdot 1 \cdot sin (x)

Multiplier les nombres :

4 \cdot 1 = 4

= 4 sin (x)

4 sin^{2} (x) sin (x) = 4 sin^{3} (x)

4 sin^{2} (x) sin (x)

Appliquer la règle de l'exposant:

a^{b} \cdot a^{c} = a^{b + c}

sin^{2} (x) sin (x) = sin^{2 + 1} (x)

= 4 sin^{2 + 1} (x)

Additionner les nombres :

2 + 1 = 3

= 4 sin^{3} (x)

= - 4 sin (x) + 4 sin^{3} (x)

= - 4 sin (x) + 4 sin^{3} (x)

= sin^{2} (x) + 4 - 4 sin^{2} (x) - 4 sin (x) + 4 sin^{3} (x)

Simplifier

sin^{2} (x) + 4 - 4 sin^{2} (x) - 4 sin (x) + 4 sin^{3} (x) : - 3 sin^{2} (x) - 4 sin (x) + 4 sin^{3} (x) + 4

sin^{2} (x) + 4 - 4 sin^{2} (x) - 4 sin (x) + 4 sin^{3} (x)

Grouper comme termes

= sin^{2} (x) - 4 sin^{2} (x) - 4 sin (x) + 4 sin^{3} (x) + 4

Additionner les éléments similaires :

sin^{2} (x) - 4 sin^{2} (x) = - 3 sin^{2} (x)

= - 3 sin^{2} (x) - 4 sin (x) + 4 sin^{3} (x) + 4

= - 3 sin^{2} (x) - 4 sin (x) + 4 sin^{3} (x) + 4

= - 3 sin^{2} (x) - 4 sin (x) + 4 sin^{3} (x) + 4

4 - 3 sin^{2} (x) - 4 sin (x) + 4 sin^{3} (x) = 0

Résoudre par substitution

4 - 3 sin^{2} (x) - 4 sin (x) + 4 sin^{3} (x) = 0

Soit :

sin (x) = u

4 - 3 u^{2} - 4 u + 4 u^{3} = 0

4 - 3 u^{2} - 4 u + 4 u^{3} = 0 : u \approx - 1.06659 \dots

4 - 3 u^{2} - 4 u + 4 u^{3} = 0

Ecrire sous la forme standard

a_{n} x^{n} + \dots + a_{1} x + a_{0} = 0

4 u^{3} - 3 u^{2} - 4 u + 4 = 0

Trouver une solution pour

4 u^{3} - 3 u^{2} - 4 u + 4 = 0

par la méthode de Newton-Raphson:

u \approx - 1.06659 \dots

4 u^{3} - 3 u^{2} - 4 u + 4 = 0

Définition de l'approximation de Newton-Raphson

f (u) = 4 u^{3} - 3 u^{2} - 4 u + 4

Trouver

f^{^{'}} (u) : 12 u^{2} - 6 u - 4

\frac{d}{d u} (4 u^{3} - 3 u^{2} - 4 u + 4)

Appliquer la règle de l'addition/soustraction:

(f \pm g)^{'} = f^{'} \pm g^{'}

= \frac{d}{d u} (4 u^{3}) - \frac{d}{d u} (3 u^{2}) - \frac{d}{d u} (4 u) + \frac{d}{d u} (4)

\frac{d}{d u} (4 u^{3}) = 12 u^{2}

\frac{d}{d u} (4 u^{3})

Retirer la constante:

(a \cdot f)^{'} = a \cdot f^{'}

= 4 \frac{d}{d u} (u^{3})

Appliquer la règle de la puissance:

\frac{d}{d x} (x^{a}) = a \cdot x^{a - 1}

= 4 \cdot 3 u^{3 - 1}

Simplifier

= 12 u^{2}

\frac{d}{d u} (3 u^{2}) = 6 u

\frac{d}{d u} (3 u^{2})

Retirer la constante:

(a \cdot f)^{'} = a \cdot f^{'}

= 3 \frac{d}{d u} (u^{2})

Appliquer la règle de la puissance:

\frac{d}{d x} (x^{a}) = a \cdot x^{a - 1}

= 3 \cdot 2 u^{2 - 1}

Simplifier

= 6 u

\frac{d}{d u} (4 u) = 4

\frac{d}{d u} (4 u)

Retirer la constante:

(a \cdot f)^{'} = a \cdot f^{'}

= 4 \frac{d u}{d u}

Appliquer la dérivée commune:

\frac{d u}{d u} = 1

= 4 \cdot 1

Simplifier

= 4

\frac{d}{d u} (4) = 0

\frac{d}{d u} (4)

Dérivée d'une constante:

\frac{d}{d x} (a) = 0

= 0

= 12 u^{2} - 6 u - 4 + 0

Simplifier

= 12 u^{2} - 6 u - 4

Soit

u_{0} = - 1

Calculer

u_{n + 1}

jusqu'à

Δ u_{n + 1} < 0.000001

u_{1} = - 1.07142 \dots : Δ u_{1} = 0.07142 \dots

f (u_{0}) = 4 (- 1)^{3} - 3 (- 1)^{2} - 4 (- 1) + 4 = 1

f^{^{'}} (u_{0}) = 12 (- 1)^{2} - 6 (- 1) - 4 = 14

u_{1} = - 1.07142 \dots

Δ u_{1} = ∣ - 1.07142 \dots - (- 1) ∣ = 0.07142 \dots

Δ u_{1} = 0.07142 \dots

u_{2} = - 1.06661 \dots : Δ u_{2} = 0.00481 \dots

f (u_{1}) = 4 (- 1.07142 \dots)^{3} - 3 (- 1.07142 \dots)^{2} - 4 (- 1.07142 \dots) + 4 = - 0.07798 \dots

f^{^{'}} (u_{1}) = 12 (- 1.07142 \dots)^{2} - 6 (- 1.07142 \dots) - 4 = 16.20408 \dots

u_{2} = - 1.06661 \dots

Δ u_{2} = ∣ - 1.06661 \dots - (- 1.07142 \dots) ∣ = 0.00481 \dots

Δ u_{2} = 0.00481 \dots

u_{3} = - 1.06659 \dots : Δ u_{3} = 0.00002 \dots

f (u_{2}) = 4 (- 1.06661 \dots)^{3} - 3 (- 1.06661 \dots)^{2} - 4 (- 1.06661 \dots) + 4 = - 0.00036 \dots

f^{^{'}} (u_{2}) = 12 (- 1.06661 \dots)^{2} - 6 (- 1.06661 \dots) - 4 = 16.05172 \dots

u_{3} = - 1.06659 \dots

Δ u_{3} = ∣ - 1.06659 \dots - (- 1.06661 \dots) ∣ = 0.00002 \dots

Δ u_{3} = 0.00002 \dots

u_{4} = - 1.06659 \dots : Δ u_{4} = 5.14172 E - 10

f (u_{3}) = 4 (- 1.06659 \dots)^{3} - 3 (- 1.06659 \dots)^{2} - 4 (- 1.06659 \dots) + 4 = - 8.25297 E - 9

f^{^{'}} (u_{3}) = 12 (- 1.06659 \dots)^{2} - 6 (- 1.06659 \dots) - 4 = 16.05100 \dots

u_{4} = - 1.06659 \dots

Δ u_{4} = ∣ - 1.06659 \dots - (- 1.06659 \dots) ∣ = 5.14172 E - 10

Δ u_{4} = 5.14172 E - 10

u \approx - 1.06659 \dots

Appliquer une division longue:

\frac{4 u ^{3} - 3 u ^{2} - 4 u + 4}{u + 1.06659 \dots} = 4 u^{2} - 7.26637 \dots u + 3.75025 \dots

4 u^{2} - 7.26637 \dots u + 3.75025 \dots \approx 0

Trouver une solution pour

4 u^{2} - 7.26637 \dots u + 3.75025 \dots = 0

par la méthode de Newton-Raphson:

Aucune solution pour

u \in R

4 u^{2} - 7.26637 \dots u + 3.75025 \dots = 0

Définition de l'approximation de Newton-Raphson

f (u) = 4 u^{2} - 7.26637 \dots u + 3.75025 \dots

Trouver

f^{^{'}} (u) : 8 u - 7.26637 \dots

\frac{d}{d u} (4 u^{2} - 7.26637 \dots u + 3.75025 \dots)

Appliquer la règle de l'addition/soustraction:

(f \pm g)^{'} = f^{'} \pm g^{'}

= \frac{d}{d u} (4 u^{2}) - \frac{d}{d u} (7.26637 \dots u) + \frac{d}{d u} (3.75025 \dots)

\frac{d}{d u} (4 u^{2}) = 8 u

\frac{d}{d u} (4 u^{2})

Retirer la constante:

(a \cdot f)^{'} = a \cdot f^{'}

= 4 \frac{d}{d u} (u^{2})

Appliquer la règle de la puissance:

\frac{d}{d x} (x^{a}) = a \cdot x^{a - 1}

= 4 \cdot 2 u^{2 - 1}

Simplifier

= 8 u

\frac{d}{d u} (7.26637 \dots u) = 7.26637 \dots

\frac{d}{d u} (7.26637 \dots u)

Retirer la constante:

(a \cdot f)^{'} = a \cdot f^{'}

= 7.26637 \dots \frac{d u}{d u}

Appliquer la dérivée commune:

\frac{d u}{d u} = 1

= 7.26637 \dots \cdot 1

Simplifier

= 7.26637 \dots

\frac{d}{d u} (3.75025 \dots) = 0

\frac{d}{d u} (3.75025 \dots)

Dérivée d'une constante:

\frac{d}{d x} (a) = 0

= 0

= 8 u - 7.26637 \dots + 0

Simplifier

= 8 u - 7.26637 \dots

Soit

u_{0} = 1

Calculer

u_{n + 1}

jusqu'à

Δ u_{n + 1} < 0.000001

u_{1} = 0.34041 \dots : Δ u_{1} = 0.65958 \dots

f (u_{0}) = 4 \cdot 1^{2} - 7.26637 \dots \cdot 1 + 3.75025 \dots = 0.48388 \dots

f^{^{'}} (u_{0}) = 8 \cdot 1 - 7.26637 \dots = 0.73362 \dots

u_{1} = 0.34041 \dots

Δ u_{1} = ∣ 0.34041 \dots - 1 ∣ = 0.65958 \dots

Δ u_{1} = 0.65958 \dots

u_{2} = 0.72346 \dots : Δ u_{2} = 0.38304 \dots

f (u_{1}) = 4 \cdot 0.34041 \dots^{2} - 7.26637 \dots \cdot 0.34041 \dots + 3.75025 \dots = 1.74019 \dots

f^{^{'}} (u_{1}) = 8 \cdot 0.34041 \dots - 7.26637 \dots = - 4.54302 \dots

u_{2} = 0.72346 \dots

Δ u_{2} = ∣ 0.72346 \dots - 0.34041 \dots ∣ = 0.38304 \dots

Δ u_{2} = 0.38304 \dots

u_{3} = 1.12038 \dots : Δ u_{3} = 0.39691 \dots

f (u_{2}) = 4 \cdot 0.72346 \dots^{2} - 7.26637 \dots \cdot 0.72346 \dots + 3.75025 \dots = 0.58690 \dots

f^{^{'}} (u_{2}) = 8 \cdot 0.72346 \dots - 7.26637 \dots = - 1.47865 \dots

u_{3} = 1.12038 \dots

Δ u_{3} = ∣ 1.12038 \dots - 0.72346 \dots ∣ = 0.39691 \dots

Δ u_{3} = 0.39691 \dots

u_{4} = 0.74896 \dots : Δ u_{4} = 0.37141 \dots

f (u_{3}) = 4 \cdot 1.12038 \dots^{2} - 7.26637 \dots \cdot 1.12038 \dots + 3.75025 \dots = 0.63017 \dots

f^{^{'}} (u_{3}) = 8 \cdot 1.12038 \dots - 7.26637 \dots = 1.69668 \dots

u_{4} = 0.74896 \dots

Δ u_{4} = ∣ 0.74896 \dots - 1.12038 \dots ∣ = 0.37141 \dots

Δ u_{4} = 0.37141 \dots

u_{5} = 1.18187 \dots : Δ u_{5} = 0.43290 \dots

f (u_{4}) = 4 \cdot 0.74896 \dots^{2} - 7.26637 \dots \cdot 0.74896 \dots + 3.75025 \dots = 0.55179 \dots

f^{^{'}} (u_{4}) = 8 \cdot 0.74896 \dots - 7.26637 \dots = - 1.27462 \dots

u_{5} = 1.18187 \dots

Δ u_{5} = ∣ 1.18187 \dots - 0.74896 \dots ∣ = 0.43290 \dots

Δ u_{5} = 0.43290 \dots

u_{6} = 0.83936 \dots : Δ u_{6} = 0.34251 \dots

f (u_{5}) = 4 \cdot 1.18187 \dots^{2} - 7.26637 \dots \cdot 1.18187 \dots + 3.75025 \dots = 0.74962 \dots

f^{^{'}} (u_{5}) = 8 \cdot 1.18187 \dots - 7.26637 \dots = 2.18860 \dots

u_{6} = 0.83936 \dots

Δ u_{6} = ∣ 0.83936 \dots - 1.18187 \dots ∣ = 0.34251 \dots

Δ u_{6} = 0.34251 \dots

u_{7} = 1.69025 \dots : Δ u_{7} = 0.85089 \dots

f (u_{6}) = 4 \cdot 0.83936 \dots^{2} - 7.26637 \dots \cdot 0.83936 \dots + 3.75025 \dots = 0.46925 \dots

f^{^{'}} (u_{6}) = 8 \cdot 0.83936 \dots - 7.26637 \dots = - 0.55149 \dots

u_{7} = 1.69025 \dots

Δ u_{7} = ∣ 1.69025 \dots - 0.83936 \dots ∣ = 0.85089 \dots

Δ u_{7} = 0.85089 \dots

u_{8} = 1.22729 \dots : Δ u_{8} = 0.46295 \dots

f (u_{7}) = 4 \cdot 1.69025 \dots^{2} - 7.26637 \dots \cdot 1.69025 \dots + 3.75025 \dots = 2.89606 \dots

f^{^{'}} (u_{7}) = 8 \cdot 1.69025 \dots - 7.26637 \dots = 6.25564 \dots

u_{8} = 1.22729 \dots

Δ u_{8} = ∣ 1.22729 \dots - 1.69025 \dots ∣ = 0.46295 \dots

Δ u_{8} = 0.46295 \dots

u_{9} = 0.89136 \dots : Δ u_{9} = 0.33593 \dots

f (u_{8}) = 4 \cdot 1.22729 \dots^{2} - 7.26637 \dots \cdot 1.22729 \dots + 3.75025 \dots = 0.85730 \dots

f^{^{'}} (u_{8}) = 8 \cdot 1.22729 \dots - 7.26637 \dots = 2.55202 \dots

u_{9} = 0.89136 \dots

Δ u_{9} = ∣ 0.89136 \dots - 1.22729 \dots ∣ = 0.33593 \dots

Δ u_{9} = 0.33593 \dots

u_{10} = 4.22467 \dots : Δ u_{10} = 3.33330 \dots

f (u_{9}) = 4 \cdot 0.89136 \dots^{2} - 7.26637 \dots \cdot 0.89136 \dots + 3.75025 \dots = 0.45139 \dots

f^{^{'}} (u_{9}) = 8 \cdot 0.89136 \dots - 7.26637 \dots = - 0.13541 \dots

u_{10} = 4.22467 \dots

Δ u_{10} = ∣ 4.22467 \dots - 0.89136 \dots ∣ = 3.33330 \dots

Δ u_{10} = 3.33330 \dots

Impossible de trouver une solution

La solution est

u \approx - 1.06659 \dots

Remplacer

u = sin (x)

sin (x) \approx - 1.06659 \dots

sin (x) \approx - 1.06659 \dots

sin (x) = - 1.06659 \dots :

Aucune solution

sin (x) = - 1.06659 \dots

- 1 \leq sin (x) \leq 1

Aucune solution

Combiner toutes les solutions

Aucune solution

Combiner toutes les solutions

Aucune solution

Vérifier les solutions en les intégrant dans l'équation d'origine

Vérifier des solutions en les intégrant dans

tan^{2} (x) - 4 sin (x) + 4 = 0

Retirer celles qui ne répondent pas à l'équation.

Aucune solution pour x \in R

Graphe

Exemples populaires

1-cos(2x)=0

1 - cos (2 x) = 0

sin(x)= 37/64

sin (x) = \frac{37}{64}

15cos^2(x)+7cos(x)-2=0

15 cos^{2} (x) + 7 cos (x) - 2 = 0

2(sin(t))^2-sin(t)-1=0

2 (sin (t))^{2} - sin (t) - 1 = 0

cos(x)=0.625

cos (x) = 0.625