Question

2cos^2theta +3sintheta=3, theta=?

Answer 1

2cos²Φ + 3 sinΦ
see.....
above written value is equal to zero only and only when 2 cos ² Φ = zero and sinΦ = 1
we know ,
2 cos²Φ = 0
cos²Φ = 0
cos Φ = 0
but,
cos 90° = 0
so theeta is 90° in this case
if we consider sin case then
sin Φ = 1
but,
sin90° = 1
so theeta = 90°
so theeta here is again 90°....
so in both cases theeta is 90°.... hence theeta is 90°

Answer 2

hy
2 cos sq theta + 3 sin theta =3

2(1-sin sq theta)+3sin theta =3

2- 2 sin sq theta + 3sin theta =3

2 sin sq theta - 3sin theta +1=0

2 sin sq theta - 2 sin theta - sin theta +1=0

2sin theta( sin theta -1)-1(sin theta -1)=0

(2sin theta -1)(sin theta -1)=0

ie theta = 30,90 ans

hope it helps uh...