Question

find all the degree values that fit between 0 < theta < 360
3cos 2 theta + 8 sin theta +5 = 0

Answer 1

cos2t=1-2*sin^2 t
so,
3*(1-2sin^2 t)+8sin t +5=0
3-6sin^2 t +8sint +5=0
simplify and solve it for sint like it's your x, after - find your t (t=theta)

Answer 2

3cos 2 theta + 8 sin theta +5 = 0,
3 [1-2 sin^2 theta] + 8 sin theta + 5 =0,
-2 sin^2 theta + 8 sin theta +8 =0.
let x = sin theta,

-2x^2 + 8x + 8 =0
now u have a quadratic problem.
solve it then you'll get sin theta = ....
to find theta, solve the above equation :)

Answer 3

sorry it's minus 6 for the coefficient of x^2 ;)