Question 911313
Use inverse functions where needed to find all solutions of the equation in the interval [0, 2 pi). (Enter your answers as a comma-separated list.)
2 sin^2 x + 9 cos x = 6
{{{2sin^2(x)+9cos(x)=6}}}
{{{2(1-cos^2(x))+9cos(x)=6}}}
2-2cos^2x+9cosx=6
2cos^2x-9cosx+4=0
(2cosx-1)(cosx-4)=0
cosx=4(reject)(-1 ≤ cosx ≤ 1
or
cosx=1/2
x=π/3, 5π/3 (in quadrants I and IV where cos>0)