Question

Find all solutions of cos^4(2x)=9/16

Answer 1

15 degrees

Explanation:

Given the trigonometry equation cos^4(2x)=9/16

cos^4(2x)=9/16

This an also be expressed as;

(cos²2x)² = 9/16

cos²2x = ±√9/16

cos²2x = ±3/4

cos2x = √3/4

cos2x = √3/2

2x = arccos √3/2

2x = 30

x = 30/2

x = 15degrees

Hence the value of x is 15 degrees