If A = 1 2 , B = 1 3 , then 2A = - Vidyadip

MCQ

If $\tan A = \frac{1}{2},\tan B = \frac{1}{3},$ then $\cos 2A = $

A
$\sin B$
✓
$\sin 2B$
C
$\sin 3B$
D
None of these

✓

Answer

Correct option: B.

$\sin 2B$

b
(b) $A + B = 45^\circ ,$

therefore $2A = 90^\circ - 2B$

$\therefore \cos 2A = \sin 2B$.

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