MCQ
$\sin2\text{A}=2\sin\text{A}$ is true when $A =$
- ✓$0^\circ$
- B$30^\circ$
- C$45^\circ$
- D$60^\circ$
✓
Answer
Correct option: A.
$0^\circ$
We are given $\sin2\text{A}=2\sin\text{A}.\cos\text{A}$
So,
$\Rightarrow\sin2\text{A}=2\sin\text{A}$
$\Rightarrow2\sin\text{A}.\cos\text{A}=2\sin\text{A}$
$\Rightarrow\cos\text{A}=1$
$\Rightarrow\cos\text{A}=\cos0^\circ$
As $\text{A}=0^\circ$
Hence the correct option is $(a)$
So,
$\Rightarrow\sin2\text{A}=2\sin\text{A}$
$\Rightarrow2\sin\text{A}.\cos\text{A}=2\sin\text{A}$
$\Rightarrow\cos\text{A}=1$
$\Rightarrow\cos\text{A}=\cos0^\circ$
As $\text{A}=0^\circ$
Hence the correct option is $(a)$
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