Question

Choose the correct option and justify your choice.
(iii)$sin2A$ = 2sinA is true when A=

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

sin 2A = 2 sin A is true when A =
=As sin 2A = sin $0^{\circ }$ = 0
2 sin A = 2sin $0^{\circ }$ = 2$\times$0 = 0
or,
sin 2A = 2sin A cos A
$\Rightarrow$2sin A cos A =2 sin A
$\Rightarrow$ 2cos A = 2 $\Rightarrow$ cos A = 1
$\Rightarrow$ A = $0^{\circ }$