Question

The value of
of cos 15
​

Answer 1

$\Large{\underline{\underline{\blue{\bold{✄Solution:}}}}}$

$→\; \cos( 15 ) \\ →\; \cos(45 - 30) \\→\; \cos(45). \cos(30) - \sin(45) .\sin(30) \\ →\; \frac{1}{ \sqrt{3} } . \frac{ \sqrt{3} }{2} - \frac{1}{ \sqrt{2} } \frac{1}{2} \\ →\; \frac{ \sqrt{3} }{2 \sqrt{2} } + \frac{1}{2 \sqrt{2} } \\→\; \frac{1}{2 \sqrt{2} } ( \sqrt{3} + 1) \\ →\; \frac{ \sqrt{3} + 1 }{2 \sqrt{2} }$

$\boxed{\pink{\sf{Cos(a-b) = Cosa.Cosb - Sina.Sinb}}}$

• Value of Cos 15° ☞ $\Large\red{\bold{\frac{1+\sqrt{3}}{2\sqrt{2}}.}}$

$\boxed{\tt{@MrSovereign}}$

Hope This Helps!!