Question

the value of theta for which 2 cos 2 theta + sin theta - 2 =0, 0°>theta> 90° is​

Answer 1

Answer:

2(1−sin

2

θ)+sinθ−2=0

2−2sin

2

θ+sinθ−2=0

−2sin

2

θ+sinθ=0

sinθ(1−2sinθ)=0

So, either sinθ=0 or 1−2sinθ=0

If sinθ=0, ⇒θ=0

0

And, if 1−2sinθ=0,

sinθ=1/2

⇒θ=30

0

.

Thus, θ=0

0

or 30

0