First slide

Trignometry

Question

Find the value of $2 \sin 45 ° \cos 15 °$

Moderate

A

$(\frac{\sqrt{3} + 2}{2})$
B

0
C

$(\frac{\sqrt{3} + 1}{2})$
D

$(\frac{\sqrt{2} + 1}{2})$

Solution

$\sin C + \sin D = 2 \sin (\frac{C + D}{2}) \cos (\frac{C - D}{2})$
$∴ \frac{C + D}{2} = 45 °$
or
$C + D = 90 °$
$\frac{C - D}{2} = 15 °$
or
$C - D = 30 °$
Solving these two equations, we get;
$C = 60 °, D = 30 °$
$∴ 2 \sin 45 ° \cos 15 ° = \sin 60 ° + \sin 30 °$
$= (\frac{\sqrt{3} + 1}{2})$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App