(1)|2-π|+|π-4|=?
已知cosa=-4/5,a∈(π,3/2π),tanb=-1/3,b∈(π/2,π),求cos(a+b)
已知sin(X+π/4)=1/3,X∈(π/2,π)求sinX
若cos(π-a)=-1/2,π/2
已知f(n)=sin[(n+1/2)π+π/4]+cos[(n-1/2)π+π/4]+tan[(n+1)π+π/4].求
已知tan(α+β)=2/5,tan(β-π/4)=1/4,试求sin(α-π/4),cos(α-π/4)
(1)函数y=sin(x+π/4),x∈(-π/2,π/2)的值域是 (2)函数y=1/2sin(π/4-2π/3)的单
若sin(π/2+x)=-4/5,x属于(π/2,π),则cos(π/3-x)=
设cos(π/4+x)=3/5,x∈(3π/4,7π/4),求(sin2x+2sin²x)/(1-tanx)
已知函数fx=(1+1/tanx)sin^x-2sin(x+π/4)sin(x-π/4)
已知tan(α+π/4)=-1/7.求(cos2α+1)/【2cos(α-π/4)*sin(α+π/4)-sin2α】的
已知f(n)=sin[(n+1\2)π+π\4]+cos[(n-1\2)+π\4]+tan[(n+1)π+π\4],求f
已知:tanA+1/tanA=5/2,A∈(π/4,π/2),求cos2A和sin(2A+π/4)的值