Question

The value of cos 15)=?

Answer 1

Hey dear here is your answer!!!!

Cos15 :-

Solution;

=>cos(45-30)
we know cos(A-B) = cosAcosB + sinAsinB

substitute the values ....

cos45cos30 - sin45sin30


Final answer will be √3+1/2√2

Hope it helps u dear..☺️☺️☺️

Answer 2

Given : The trigonometric term is = cos 15°

To find : Value of the given trigonometric term.

Solution :

We can simply solve this mathematical problem by using the following mathematical process.

Now,

We can write the given trigonometric term in the following way :

= cos 15°

= cos (45° - 30°)

= (cos 45° × cos 30°) + (sin 45° × sin 30°)

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

$= \frac{ \sqrt{3} }{2 \sqrt{2} } + \frac{1}{2 \sqrt{2} }$

$= \frac{ \sqrt{3} + 1 }{2 \sqrt{2} }$

(This will be considered as the final result.)

Used formula :

• cos (A-B) = cosA cosB + sinA sinB

Hence, the value of cos 15° is (√3+1)/(2√2)