Question

Please help, performance task: trigonometric identities

Answer 1

The answers are given below:

What is Trigonometry?

Trigonometry is a branch of mathematics that studies relationships between the sides and angles of triangles.

1. (cos x. cos y)(tan x + tan y) = sin (x+ y)

  (cos x. cos y)(tan x + tan y)

= cos x. cos y (sinx/ cos x + sin y/ cos y)

= sin x cos y + sin y cos x

= sin (x+ y)    [ sin ( x +y)]= sin x cos y + sin y cos x

= RHS

3. $-\sin ^2\left(x\right)-\cos \left(2x\right)=0$

Using identity

$-\cos ^2\left(x\right)=0$

cos ² x=0

Applying $x^{n} =0$ then x=0

So, cos x =0

General solution will be $x=\frac{\pi }{2}+2\pi n,\:x=\frac{3\pi }{2}+2\pi n$.

Learn more about trigonometry here:

brainly.com/question/12537661

#SPJ1