Question

Cos square 15 - cos square 75​

Answer 1

Answer:

cos^2 15 - cos^2 75

cos^2(45-15)- cos^2(75-45)

cos^2 30- cos^2 30

(√3/2)^2-(1/2)^2

3/4-1/4

3-1/4

2/4

1/2