# How would I solve this? 2sin^2 x - cos(x + pi/2) - 1 = 0 for -pi < x < pi

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I’m really sorry I’m not too sure how to do all the symbols.

Thanks to anyone that can help.

I’m really sorry I’m not too sure how to do all the symbols.

Thanks to anyone that can help.

##### 1 Answer

Jun 18, 2018

#### Explanation:

Note.

Solve this quadratic equation foe sin x.

Since a + b + c = 0, use shortcut. The 2 real roots are:

sin x = 1, and

a. sin x = 1 -->

b.

Trig table and unit circle give 2 solutions for x:

Answers for (-pi, pi):