襄阳老河口天气预报:tan(π/4+θ)+tan(π/4-θ)=4,cos2θ=?

tan π/4 = tan(π/4+θ)+tan(π/4-θ)=4,cos2θ=? tan(π/4+α)-tan(π/4-α)=2tan2α 求证:tan(π/4+α)-tan(π/4-α)=2tan2α 已知α,β≠Kπ/2 且tanα-tanβ=2tanαtanαtanβ (1)已知tan(π/4+α)=2,求tanα,sin2α+sin^2α+cos2α 已知α,β≠Kπ/2 且tanα-tanβ=2tanαtanαtanβ 求证sin（2α＋β）/sinβ=3 3已知α+β=π／4，则（tanα+1）（tanβ+1）= 已知Sin2a=A,Cos2a=B,求tan(π/4+a) 函数f(x)=tan(x+π/4)的单增区间怎么算？