Question

If 2cos60°cos 10º=CosA+cosB then the value of A is​

Answer 1

Step-by-step explanation:

If 2cos60°cos 10º=CosA+cos50

then the value of A

Answer 2

Given:

2cos60°cos 10º=CosA+cosB

To find:

The value of A.

Solution:

If 2cos60°cos 10º=CosA+cosB then the value of A is​ 70°.

We can solve the above mathematical problem using the following approach.

$We know that-\\\\ 2 \cos x \cos y=\cos (x+y)+\cos (x-y) \\\\ Now, 2 \cos 60^\circ\cos 10^\circ=\cos (60+10)^{\circ}+\cos (60-10)^{\circ} =\cos 70^{\circ}+\cos 50^{\circ}$

So,

$\cos 70^{\circ}+\cos 50^{\circ} = \cos A + \cos B\\\\On comparing both the sides of the above equation, we get:\\\\A = 70^{\circ}, B = 50^{\circ}.$

Therefore, the value of A is 70°.