Simplify the expression:
sin⁴(x) - cos⁴(x)
Show answer & explanation
Correct answer: D
Explanation
sin⁴x − cos⁴x
According to the formula:
a² − b² = (a − b)(a + b)
sin²x + cos²x = 1
sin⁴x − cos⁴x= (sin²x − cos²x)(sin²x + cos²x)
= (sin²x − cos²x)(1)
= sin²x − cos²x