Question

Cosα=7/25, 3π/2‹α‹2π, нужно найти sin2α, cos2α, tg2α

Answer 1

Cosα=7/25
sinα=+- корень из(1-Cos^2α)=+-24/25
т.к. 3π/2‹α‹2π, то sinα=-24/25
sin2α=2sina*cosa=-0,5376
cos2α=cos^2a-sin^2a=25
tg2α=sin2α/cos2α=-0,021468