Question

Number 1)
sin^2 45 + cos^2 45 -sin^2 90
Number 2)
Sin 0 . Cos 90 - sin 90
Number 3)
Cos^2 90 - cos^2 30

Answer 1

no. 1 = sin²45+cos²45 - 1
1 -1 = 0
no.2 = 0-1 = -1 ans.
no.3. = 3/4 ans.

Answer 2

Hope you find it helpful
It was simple though
Thank you