How do you find all the solutions of the following equation in the interval [0, 2pi)? 48sin^2x = 48-24cosx

1 Answer
Jun 22, 2018

x={pi/2,(3pi)/2,pi/3,(5pi)/3}x={π2,3π2,π3,5π3}

Explanation:

48sin^2x=48-24cosx48sin2x=4824cosx
2sin^2x=2-cosx2sin2x=2cosx
2(1-cos^2x)=2-cosx2(1cos2x)=2cosx
2-2cos^2x=2-cosx22cos2x=2cosx
0=2cos^2x-cosx0=2cos2xcosx
0=cosx(2cosx-1)0=cosx(2cosx1)
cosx=0cosx=0 or 2cosx-1=02cosx1=0
x=pi/2,(3pi)/2x=π2,3π2 or x=pi/3,(5pi)/3x=π3,5π3