Question

Find all solutions for this equation:
2cos^2(x)+sin(x)-2=0

Answer 1

TIp: \(\cos^2(x)+\sin^2(x)=1\)

Answer 2

I'm sorry, I don't really understand how to use that. My teacher didn't explain it well.

Answer 3

\(\cos^2(x)=1-\sin^2(x)\)
Is that more clear now?

Answer 4

A little bit.

Answer 5

\[
\begin{align*}
2\cos^2(x)+\sin(x)-2&=0\\
2(1-\sin^2(x))+\sin(x)-2&=0\\
2-2\sin^2(x)+\sin(x)-2&=0\\
-2\sin^2(x)+\sin(x)&=0
\end{align*}
\]
More clear now?

Answer 6

Yeah, so after doing that would I continue using pythagorean?

Answer 7

Nope. Just factor out \(\sin(x)\) and solve it.

Answer 8

Ok, thank you!