Question #23b80

1 Answer
Jan 26, 2018

theta= 60^o or theta= 300^oθ=60oorθ=300o

Explanation:

2cos^2θ−3sinθ=0

2(1-sin^2theta)−3sinθ=0 because cos^2θ+sin^2theta=1

2-2sin^2theta−3sinθ=0

2sin^2theta+3sinθ-2=0

sinθ=(-3+-sqrt(3^2-4*2*(-2)))/(2*2)

sinθ=(-3+-sqrt(9+16))/4

sinθ=(-3+-sqrt(25))/4=(-3+-5)/4

sin theta=-8/4 or sin theta= 2/4

sin theta=-2 or sin theta= 1/2

theta notin RR or sin theta= 1/2

theta= 60^o or theta= (-60^o +360^o)

theta= 60^o or theta= 300^o