Question

Find the solution for sin^2x = -2 + 3 cosx

I did this:

1 - cos^2 = -2 + 3cosx
-cos^2x = -3 + 3 cosx
cos^2x + 3 cosx -3

(x )(x )

Answer 1

now let cosx = t, then
t^2+3t-3=0
solve this. Later come back to x

Answer 2

cos^2x + 3 cosx -3 should be
cos^2x + 3 cosx -3 = 0

Answer 3

yes but that doesn't factor

Answer 4

I got It!

Answer 5

Use the quadratic formula to solve.

Answer 6

i did quadratic formula

Answer 7

What about cosx^2= 3+4sinx

i got it down to sinx^2+4sinx+2

did quadratic

and got -.626
and 3.767 but my answer is incorrect for some reason