sec x=?csc x=?

sec x=?csc x=? 化简：csc（x）-sec（x）= y=sec^2x+csc^2x求导 f(x)=|sin x+cos x+tan x+cot x+sec x+csc x|最小值 tan x /(1-cot x) + cot x /(1-tanx) = 1+ sec x csc x 谁能帮我解一下“tan x + cot x = sec x csc x” f(x)=|sin x+cos x+tan x+cot x+sec x+csc x|最小值答对马上采纳, y=sec^2(x/a)+csc^2(x/a)的导数怎么求? 证明(tan^2x-cot^2x)/(sin^2x-cos^2x)=sec^2x+csc^2x 证明(tan^2x-cot^2x)/(sin^2x+cos^2x)=sec^2x+csc^2x csc(-x)= y = sec (x) + csc (x) 求导,之后代入x = 3pi / 4 求值,要较详细步骤!