证明 (-sin^2(x))/(sin(x))=-sin(x)

解答

证明

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

真

求解步骤

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

调整左侧

\frac{- sin ^{2} ( x )}{sin ( x )}

化简

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

\frac{- sin ^{2} ( x )}{sin ( x )}

使用分式法则:

\frac{- a}{b} = - \frac{a}{b}

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

约分:

sin (x)

= - sin (x)

= - sin (x)

我们已展示，在两侧可以有相同的形式

\Rightarrow 真

p ro v e cos (4 x) = 8 cos^{4} (x)

p ro v e ((1 + cot (a) - csc (a)) (1 + tan (a) + sec (a))) = 2

p ro v e cos (x) + 1 (cos (x) - 1) = cos^{2} (x) - 1

p ro v e sin (3 x) = 3 sin (x) - 4 sin (3 x)

p ro v e 2 cos^{2} (A) = 1 + cos (2 A)