sin(x-45°)=?,cos(x-45°)=?,tan(x-45°)=?

已知tan=2,求(cos x+sin x)/(cos x-sin x)+sin^2x 证明(1-2sin x cos x )/(cos^2x-sin^2x)=(1-tan x)/(1+tan x) f(x)=|sin x+cos x+tan x+cot x+sec x+csc x|最小值 证明1-tan^2x/1+tan^2x=cos^2x-sin^2x 证明：(1 + tan x) / (sin x + cos x) = 1 / cos x tan(x+45)-tan(45-x)=? 证明 tan(x+Δx)-tanx=sinΔx/cos(x+Δx)cosx tan(x+y)tan(x-y)=sin^2x-sin^2y/cos^2x-sin^2y 顺便问一下. tan,sin, 已知tan x=-3/4,求sin x ,cos x ,cot x 的值. f(x)=|sin x+cos x+tan x+cot x+sec x+csc x|最小值答对马上采纳, 已知(x)=[sin(π-x)cos(2π-x)tan(-x+π)]/[cos(-π/2+x)] 求证 （1—tan^2X)/(1+tan^2X)=cos^2X—sin^2X