已知cos(θ+π/4)=3/5,π/2

已知cos(θ+π/4)=3/5,π/2 已知 sin(θ+kπ)=-2cos (θ+kπ) 求 ⑴4sinθ-2cosθ/5cosθ+3sinθ; ⑵(1/4) 已知tan(θ+π/4)=-2,求cosθ平方+sinθcosθ-1 ①化简[sin(2π+α)*cos(7π-α)]/cos(-α)②已知cosθ=-3/5,θ∈(π/2,π),求sin( 急：：已知sin(3π+a)=2cos(a-4π),求(5sin(π/2+a)+cos(π/2-a))/(2cos(π+ 已知tanθ=3,求(3cosθ-5sin^2θcosθ)/sin(π-θ)的值 已知(4sinθ-2cosθ)/(3sinθ+5cosθ)=6/11,求5cos^2θ/(sin^2θ+2sinθcos 已知cosα=-3/5,α属于(π/2,2π)则cos(α-π/4)= 已知cos(π/4+x)=3/5 ,0 已知cosθ=-3/5,θ∈（π/2,π) 求2/sin2θ-cosθ/sinθ+tan^2(θ/2)+sin^4(θ/ 已知sinθ+cosθ=1/5,且π/2≤θ≤3π/4,则cos^2-θsin^2θ的值 已知cos（π4