## ksaimouli 2 years ago solve for x cos^2x-sin^2x=sin x

1. ksaimouli

$\cos^2x-\sin^2x =sinx$

2. eyust707

I see trig... I see trig stuff squared... im thinkin trig identities right off the bat!

3. terenzreignz

cox 2x comes to mind...

4. terenzreignz

but it's useless, I think?

5. eyust707

no i like the thinking!

6. terenzreignz

LOL, this is a quadratic equation in disguise

7. terenzreignz

cos^2 x = 1 - sin^2 x right? so we can turn it into... 1 - sin^2 x - sin^2 x = sin x

8. colorful

$\cos^2x-\sin^2=1-2\sin^2x$

9. colorful

oops :P ditto

10. terenzreignz

Oh, you can do it from here? great :)

11. colorful

I'm not the asker @ksaimouli can you take it from here?

12. terenzreignz

derp, I forgot about that (sorry)