Express as a product

Question

4sin^2(a)-3

I know formula but not how to apply

Answer 1

4sin²(a) - 3 expressed as a product:

let x = sin(a)

We have 4x^2 -3 = (2x-√3)(2x+√3)

Substitute back in: (2Sin(a) - √3)(2Sin(a) + √3)