Question

A= 30⁰ then show that cos3A= 4cos³A−3cosA​

Answer 1

Proved

Step-by-step explanation:

Cos(3*30) = 4 (cos30)^3 - 3 cos30

0 = 4 *( 3√3 ÷ 8 ) - ( 3 ×√3 ÷ 2)

0= (3√3 ÷ 2 ) - (3√3 ÷ 2 )

0= 0

Hence proved