sinθ-cosθ=1/5,θ∈(o,π),求sin2θ

问题描述:

sinθ-cosθ=1/5,θ∈(o,π),求sin2θ

sinθ-cosθ=1/5
(sinθ-cosθ)2=1-sin2θ =1/25
sin2θ =24/25

sinθ-cosθ=1/5
(sinθ-cosθ)^2=1-2sinθcosθ=1-sin2θ=1/25
sin2θ=24/25