zs

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

受欢迎的三角函数 >

csc(x)-sin(x)=cos(x)cot(3x-50)

解答

csc (x) - sin (x) = cos (x) cot (3 x - 50)

解答

x = \frac{π}{2} + 2 πn, x = \frac{3 π}{2} + 2 πn, x = πn + 25, x = \frac{π}{2} + 25 + πn

+1

度数

x = 9 0^{\circ} + 36 0^{\circ} n, x = 27 0^{\circ} + 36 0^{\circ} n, x = 1432.39448 \dots^{\circ} + 18 0^{\circ} n, x = 1522.39448 \dots^{\circ} + 18 0^{\circ} n

求解步骤

csc (x) - sin (x) = cos (x) cot (3 x - 50)

两边减去

cos (x) cot (3 x - 50)

csc (x) - sin (x) - cos (x) cot (3 x - 50) = 0

用 sin, cos 表示

csc (x) - sin (x) - cos (x) cot (- 50 + 3 x)

使用基本三角恒等式:

csc (x) = \frac{1}{sin ( x )}

= \frac{1}{sin ( x )} - sin (x) - cos (x) cot (- 50 + 3 x)

使用基本三角恒等式:

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

= \frac{1}{sin ( x )} - sin (x) - cos (x) \frac{cos ( - 50 + 3 x )}{sin ( - 50 + 3 x )}

化简

\frac{1}{sin ( x )} - sin (x) - cos (x) \frac{cos ( - 50 + 3 x )}{sin ( - 50 + 3 x )} : \frac{sin ( 3 x - 50 ) - sin ^{2} ( x ) sin ( 3 x - 50 ) - cos ( - 50 + 3 x ) cos ( x ) sin ( x )}{sin ( x ) sin ( 3 x - 50 )}

\frac{1}{sin ( x )} - sin (x) - cos (x) \frac{cos ( - 50 + 3 x )}{sin ( - 50 + 3 x )}

乘

cos (x) \frac{cos ( - 50 + 3 x )}{sin ( - 50 + 3 x )} : \frac{cos ( 3 x - 50 ) cos ( x )}{sin ( - 50 + 3 x )}

cos (x) \frac{cos ( - 50 + 3 x )}{sin ( - 50 + 3 x )}

分式相乘:

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

= \frac{cos ( - 50 + 3 x ) cos ( x )}{sin ( - 50 + 3 x )}

= \frac{1}{sin ( x )} - sin (x) - \frac{cos ( 3 x - 50 ) cos ( x )}{sin ( 3 x - 50 )}

将项转换为分式:

sin (x) = \frac{sin ( x )}{1}

= \frac{1}{sin ( x )} - \frac{sin ( x )}{1} - \frac{cos ( - 50 + 3 x ) cos ( x )}{sin ( - 50 + 3 x )}

sin (x), 1, sin (- 50 + 3 x)

的最小公倍数:

sin (x) sin (3 x - 50)

sin (x), 1, sin (- 50 + 3 x)

最小公倍数 (LCM)

计算出由至少在以下一个因式表达式中出现的因子组成的表达式

= sin (x) sin (3 x - 50)

根据最小公倍数调整分式

将每个分子乘以其分母转变为最小公倍数所要乘以的同一数值

sin (x) sin (3 x - 50)

对于

\frac{1}{sin ( x )} :

将分母和分子乘以

sin (3 x - 50)

\frac{1}{sin ( x )} = \frac{1 \cdot sin ( 3 x - 50 )}{sin ( x ) sin ( 3 x - 50 )} = \frac{sin ( 3 x - 50 )}{sin ( x ) sin ( 3 x - 50 )}

对于

\frac{sin ( x )}{1} :

将分母和分子乘以

sin (x) sin (3 x - 50)

\frac{sin ( x )}{1} = \frac{sin ( x ) sin ( x ) sin ( 3 x - 50 )}{1 \cdot sin ( x ) sin ( 3 x - 50 )} = \frac{sin ^{2} ( x ) sin ( 3 x - 50 )}{sin ( x ) sin ( 3 x - 50 )}

对于

\frac{cos ( - 50 + 3 x ) cos ( x )}{sin ( - 50 + 3 x )} :

将分母和分子乘以

sin (x)

\frac{cos ( - 50 + 3 x ) cos ( x )}{sin ( - 50 + 3 x )} = \frac{cos ( - 50 + 3 x ) cos ( x ) sin ( x )}{sin ( - 50 + 3 x ) sin ( x )}

= \frac{sin ( 3 x - 50 )}{sin ( x ) sin ( 3 x - 50 )} - \frac{sin ^{2} ( x ) sin ( 3 x - 50 )}{sin ( x ) sin ( 3 x - 50 )} - \frac{cos ( - 50 + 3 x ) cos ( x ) sin ( x )}{sin ( - 50 + 3 x ) sin ( x )}

因为分母相等，所以合并分式:

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

= \frac{sin ( 3 x - 50 ) - sin ^{2} ( x ) sin ( 3 x - 50 ) - cos ( - 50 + 3 x ) cos ( x ) sin ( x )}{sin ( x ) sin ( 3 x - 50 )}

= \frac{sin ( 3 x - 50 ) - sin ^{2} ( x ) sin ( 3 x - 50 ) - cos ( - 50 + 3 x ) cos ( x ) sin ( x )}{sin ( x ) sin ( 3 x - 50 )}

\frac{sin ( - 50 + 3 x ) - sin ( - 50 + 3 x ) sin ^{2} ( x ) - cos ( - 50 + 3 x ) cos ( x ) sin ( x )}{sin ( - 50 + 3 x ) sin ( x )} = 0

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

sin (- 50 + 3 x) - sin (- 50 + 3 x) sin^{2} (x) - cos (- 50 + 3 x) cos (x) sin (x) = 0

使用三角恒等式改写

sin (- 50 + 3 x) - sin (- 50 + 3 x) sin^{2} (x) - cos (- 50 + 3 x) cos (x) sin (x)

使用毕达哥拉斯恒等式:

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

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

= sin (- 50 + 3 x) - sin (- 50 + 3 x) (1 - cos^{2} (x)) - cos (- 50 + 3 x) cos (x) sin (x)

化简

sin (- 50 + 3 x) - sin (- 50 + 3 x) (1 - cos^{2} (x)) - cos (- 50 + 3 x) cos (x) sin (x) : cos^{2} (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) cos (x) sin (x)

sin (- 50 + 3 x) - sin (- 50 + 3 x) (1 - cos^{2} (x)) - cos (- 50 + 3 x) cos (x) sin (x)

乘开

- sin (- 50 + 3 x) (1 - cos^{2} (x)) : - sin (- 50 + 3 x) + cos^{2} (x) sin (- 50 + 3 x)

- sin (- 50 + 3 x) (1 - cos^{2} (x))

使用分配律:

a (b - c) = ab - a c

a = - sin (- 50 + 3 x), b = 1, c = cos^{2} (x)

= - sin (- 50 + 3 x) \cdot 1 - (- sin (- 50 + 3 x)) cos^{2} (x)

使用加减运算法则

- (- a) = a

= - 1 \cdot sin (- 50 + 3 x) + cos^{2} (x) sin (- 50 + 3 x)

乘以:

1 \cdot sin (- 50 + 3 x) = sin (- 50 + 3 x)

= - sin (- 50 + 3 x) + cos^{2} (x) sin (- 50 + 3 x)

= sin (- 50 + 3 x) - sin (- 50 + 3 x) + cos^{2} (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) cos (x) sin (x)

同类项相加:

sin (3 x - 50) - sin (3 x - 50) = 0

= cos^{2} (x) sin (3 x - 50) - cos (3 x - 50) cos (x) sin (x)

= cos^{2} (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) cos (x) sin (x)

cos^{2} (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) cos (x) sin (x) = 0

分解

cos^{2} (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) cos (x) sin (x) : cos (x) (cos (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) sin (x))

cos^{2} (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) cos (x) sin (x)

使用指数法则:

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

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

= cos (x) cos (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) cos (x) sin (x)

因式分解出通项

cos (x)

= cos (x) (cos (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) sin (x))

cos (x) (cos (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) sin (x)) = 0

分别求解每个部分

cos (x) = 0 or cos (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) sin (x) = 0

cos (x) = 0 : x = \frac{π}{2} + 2 πn, x = \frac{3 π}{2} + 2 πn

cos (x) = 0

cos (x) = 0

的通解

cos (x)

周期表（周期为

2 πn

）：

x 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} \frac{π}{2} \frac{2 π}{3} \frac{3 π}{4} \frac{5 π}{6} cos (x) 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} x π \frac{7 π}{6} \frac{5 π}{4} \frac{4 π}{3} \frac{3 π}{2} \frac{5 π}{3} \frac{7 π}{4} \frac{11 π}{6} cos (x) - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2} 0 \frac{1}{2} \frac{2}{2} \frac{3}{2}

x = \frac{π}{2} + 2 πn, x = \frac{3 π}{2} + 2 πn

x = \frac{π}{2} + 2 πn, x = \frac{3 π}{2} + 2 πn

cos (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) sin (x) = 0 : x = πn + 25, x = \frac{π}{2} + 25 + πn

cos (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) sin (x) = 0

使用三角恒等式改写

cos (x) sin (- 50 + 3 x) - cos (- 50 + 3 x) sin (x)

使用角差恒等式:

sin (s) cos (t) - cos (s) sin (t) = sin (s - t)

= sin (- 50 + 3 x - x)

sin (- 50 + 3 x - x) = 0

sin (- 50 + 3 x - x) = 0

的通解

sin (x)

周期表（周期为

2 πn

"）：

x 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} \frac{π}{2} \frac{2 π}{3} \frac{3 π}{4} \frac{5 π}{6} sin (x) 0 \frac{1}{2} \frac{2}{2} \frac{3}{2} 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} x π \frac{7 π}{6} \frac{5 π}{4} \frac{4 π}{3} \frac{3 π}{2} \frac{5 π}{3} \frac{7 π}{4} \frac{11 π}{6} sin (x) 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2}

- 50 + 3 x - x = 0 + 2 πn, - 50 + 3 x - x = π + 2 πn

- 50 + 3 x - x = 0 + 2 πn, - 50 + 3 x - x = π + 2 πn

解

- 50 + 3 x - x = 0 + 2 πn : x = πn + 25

- 50 + 3 x - x = 0 + 2 πn

同类项相加:

3 x - x = 2 x

- 50 + 2 x = 0 + 2 πn

0 + 2 πn = 2 πn

- 50 + 2 x = 2 πn

将

50

到右边

- 50 + 2 x = 2 πn

两边加上

50

- 50 + 2 x + 50 = 2 πn + 50

化简

2 x = 2 πn + 50

2 x = 2 πn + 50

两边除以

2

2 x = 2 πn + 50

两边除以

2

\frac{2 x}{2} = \frac{2 πn}{2} + \frac{50}{2}

化简

\frac{2 x}{2} = \frac{2 πn}{2} + \frac{50}{2}

化简

\frac{2 x}{2} : x

\frac{2 x}{2}

数字相除:

\frac{2}{2} = 1

= x

化简

\frac{2 πn}{2} + \frac{50}{2} : πn + 25

\frac{2 πn}{2} + \frac{50}{2}

数字相除:

\frac{2}{2} = 1

= πn + \frac{50}{2}

数字相除:

\frac{50}{2} = 25

= πn + 25

x = πn + 25

x = πn + 25

x = πn + 25

解

- 50 + 3 x - x = π + 2 πn : x = \frac{π}{2} + 25 + πn

- 50 + 3 x - x = π + 2 πn

同类项相加:

3 x - x = 2 x

- 50 + 2 x = π + 2 πn

将

50

到右边

- 50 + 2 x = π + 2 πn

两边加上

50

- 50 + 2 x + 50 = π + 2 πn + 50

化简

2 x = π + 2 πn + 50

2 x = π + 2 πn + 50

两边除以

2

2 x = π + 2 πn + 50

两边除以

2

\frac{2 x}{2} = \frac{π}{2} + \frac{2 πn}{2} + \frac{50}{2}

化简

\frac{2 x}{2} = \frac{π}{2} + \frac{2 πn}{2} + \frac{50}{2}

化简

\frac{2 x}{2} : x

\frac{2 x}{2}

数字相除:

\frac{2}{2} = 1

= x

化简

\frac{π}{2} + \frac{2 πn}{2} + \frac{50}{2} : \frac{π}{2} + 25 + πn

\frac{π}{2} + \frac{2 πn}{2} + \frac{50}{2}

对同类项分组

= \frac{π}{2} + \frac{50}{2} + \frac{2 πn}{2}

数字相除:

\frac{50}{2} = 25

= \frac{π}{2} + 25 + \frac{2 πn}{2}

数字相除:

\frac{2}{2} = 1

= \frac{π}{2} + 25 + πn

x = \frac{π}{2} + 25 + πn

x = \frac{π}{2} + 25 + πn

x = \frac{π}{2} + 25 + πn

x = πn + 25, x = \frac{π}{2} + 25 + πn

合并所有解

x = \frac{π}{2} + 2 πn, x = \frac{3 π}{2} + 2 πn, x = πn + 25, x = \frac{π}{2} + 25 + πn

作图

流行的例子

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

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

tan^2(t)-sec^2(t)=1

tan^{2} (t) - sec^{2} (t) = 1

solvefor x,z=sin(2x+3y)

so l v e f or x, z = sin (2 x + 3 y)

4cos(x)+1=2cos(x)

4 cos (x) + 1 = 2 cos (x)

cos(2x)+cos(4x)+cos(6x)=0

cos (2 x) + cos (4 x) + cos (6 x) = 0