Question

What is cos 5x + cos 3x ?

Answer 1

Using the formula

cos A + cos B = 2 cos(A + B)/2 cos(A – B)/2,

we get = 2cos4x cosx

Answer 2

Answer:

❀ʀᴇǫᴜɪʀᴇᴅ ᴀɴsᴡᴇʀ:

x=n (180)/x=1/4n(180)

the general solution of cosx is 2 n (180)+_y

by solving we can get

5 x=2n(180)+3x.

5x=2n(180)-3x

$\sf\blue{hope \: this \: helps \: you!! \: }$