Question

1. (-8cosxsinx+4cos2x)^2 +(4cosx^2+8sinxcosx)^2
2. cos(α-β)cosβ-sin(α-β)sinβ
3. 1+(sinx-cosx)(sinx+cosx)
4. (cosβ-cotβ)(cosβ+cotβ)

Answer 1

I tried these but for 4 I seemed to get a reasonable answer: cos^2(β)-cot^2(β)

How does that look? Please correct me if I'm wrong - it felt too simple.

Answer 2

cos^2(β)-cot^2(β) can be simplified futher.

cot = 1/tan = cos/sin