Verifying identity plz helpp!
cos(x+y) + cos(x-y) = 2cosx cosy

2cosx cosy = 2cosx cosy

Step-by-step explanation:

cos(x+y) + cos(x-y) = 2cosx cosy

Use the formula for "Functions of the sum of two angles" and the "Function of the Difference of Two Angles" and substitute that in.

(Cosx cosy - sinx siny) + (cosx cosy + sinx siny)

Drop the parentheses

Cosx cosy - sinx siny + cosx cosy + sinx siny

Sinx siny can cancel

Cosx cosy + cosx cosy

This can be simplified to

2cosx cosy

62.5 paisa

step-by-step explanation:

4000*70 = 280000

280000-(2000*90) = 100000

4000-2400 = 1600

100000/1600 = 62.5

( give brainliest)