Question

Please!!!!! help I will give the brainlist.

Answer 1

The  trigonometric formula (or identity) should you use to help simplify and solve the equation is $cos2x = 1-2sin^2x$

Trigonometry identity

Given the trigonometry identity

• $\cos(2x) - \sin(x) = 1$

According to trigonometry identity

• $cos(2x) = cos^2x-sin^2x$

Also since $cos^2x = 1-sin^2x$, the expression becomes;

$cos2x = (1-sin^2x)-sin^2x\\ cos2x = 1- 2sin^2x$

To simplify the function given, you will substitute $cos2x = 1-2sin^2x$ into the original equation to have:

$\cos(2x) - \sin(x) = 1\\ (1-2sin^2x)-sinx=1$

Hence the  trigonometric formula (or identity) should you use to help simplify and solve the equation is $cos2x = 1-2sin^2x$

Learn more on trig identity here: brainly.com/question/24496175