MCQ
$3 \sin ^2 \theta+4 \cos ^2 \theta$ is cqual to
- A1
- B2
- C$\sin ^2 \theta+3$
- ✓$\cos ^2 \theta+3$
✓
Answer
Correct option: D.
$\cos ^2 \theta+3$
(D)$\cos ^2 \theta+3$
$3 \sin ^2 \theta+4 \cos ^2 \theta=\left(3 \sin ^2 \theta+3 \cos ^2 \theta\right)+\cos ^2 \theta$
$=3\left(\sin ^2 \theta+\cos ^2 \theta\right)+\cos ^2 \theta=3+\cos ^2 \theta$
$3 \sin ^2 \theta+4 \cos ^2 \theta=\left(3 \sin ^2 \theta+3 \cos ^2 \theta\right)+\cos ^2 \theta$
$=3\left(\sin ^2 \theta+\cos ^2 \theta\right)+\cos ^2 \theta=3+\cos ^2 \theta$
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