How do I solve for all real values of x in this equation 2 cos² x = 3 sin x ?

1 Answer
Feb 22, 2018

x=pi/6+2kpix=π6+2kπ
x=(5pi)/6+2kpix=5π6+2kπ

Explanation:

2cos^2x=3sinx2cos2x=3sinx
2*(1-sin^2x)=3sinx2(1sin2x)=3sinx
2-2sin^2x=3sinx22sin2x=3sinx
2sin^2x+3sinx-2=02sin2x+3sinx2=0

sqrt(∆)=sqrt(25)=5
t_1=(-3-5)/4=-2
t_2=(-3+5)/4=1/2

sinx=1/2

x=pi/6+2kpi
x=(5pi)/6+2kpi

k is real