已知cos θ=1/3,θ∈(0,π),则cos(3π/2+2θ)
问题描述:
已知cos θ=1/3,θ∈(0,π),则cos(3π/2+2θ)
答
cos(3π/2+2θ)=sin(2θ)=2*sin(θ)*cos(θ),再根据sin(θ)^2+ cos(θ)^2 = 1(cos此处取正值), 即可求出答案,自己算一算吧,很简单
已知cos θ=1/3,θ∈(0,π),则cos(3π/2+2θ)
cos(3π/2+2θ)=sin(2θ)=2*sin(θ)*cos(θ),再根据sin(θ)^2+ cos(θ)^2 = 1(cos此处取正值), 即可求出答案,自己算一算吧,很简单