Question

help solve the given equation sin^2x-2sin x-3=0

Answer 1

you want to? simplify? find x? what? ^_^

Answer 2

use substitution
assign u = sinx
then
u^2 -2u -3 = 0
Factor
-3*1 = -3
-3+1 = -2
(u-3)(u+1) =0
u=3
u=-1
replace u back with sinx and solve for x
sinx = 3, 3 is outside range of function so no solution
sinx = -1
look at unit circle sinx is -1 when x =3pi/2