Question

If sin A + sin²A = 1, then the value of the expression (cos² A + cos⁴A) =

• A. 1
• B. 1/2
• C. 2
• D. 3

Answer 1

Answer:

A. 1

sin²𝚹 + cos²𝚹 = 1 sin A + sin²A = 1 sin A = 1 - sin²A (sin A)² = (cos² A)² sin²A = cos⁴ A 1- cos²A = cos⁴ A = cos ⁴ A + cos² A