sec x -1 ~ 2x^2错了 是sec x-1 ~ 1/2(x^2)

sec x -1 ~ 2x^2错了 是sec x-1 ~ 1/2(x^2) sec x / (1+x^2),求dy/dx忘打了--- y= （sec x) / (1+x^2) tan（x)sec^2(x)dx,secx的导是secxtanx就是sec(x)d(sec(x)) 但tanx的导是sec^2(x）就是tanxd(tanx)了? 数学中Sec是啥意思极限x趋向于派/2,(1+Cos x)的2sec x次方 ∫secx/sec^2x-1 dx 化简sec(x)^2-1如题, 请解释高数例题：1、求∫sec xdx 2、∫sin√xdx （不知是我错了还是教材错了?）1、求∫sec xdx ∫sec xdx = ∫1/cosx dx=∫cosx/cos^2 x dx=∫dsinx/1-sin^2 x=∫1/2(1/1-sinx + 1/1+sinx)dx=1/2 ln| 1+sinx/1-sinx |+C=1/2 ln(1+s 求(sec x)^2积分, sec^2(7x)积分 ∫ sec^2 x dx 证明sec^2 x + csc^2 x = sec^2 x × csc^2 x右边是相乘1 + 2 = 2 × 1 ∫1/x^2*sec^2(1/x) sec x-tanx怎么能化简成2/(1+tan(x/2)), sec^2x-1等于tan^2x? ∫1/根号x*sec^2(1-根号x)dx ∫sec^2 x / √ tan x +1 dx 若x=1,sec^2x,等于多少 求lim (sec^2 x求极限lim (sec^2 x - 1 )/(1-cos x) X-0请写出过程,