Question

Упростить:4/sin^2a-4 ctg^2a

Answer 1

4/Sin²α-4 Ctg²α = 4/Sin²α - 4Cos²α/Sin²α = (4 - 4Cos²α)/Sin²α=
=4(1 - Cos²α)/Sin²α = 4Sin²α/Sin²α = 4