、常用的等价无穷小x sinxtan xarcsinxarctan xln(1 + X)x , e -1ax-1 x In aa(1+x)-1 为任意实数，不一一定是 整数1-cosx增加x -sin xtan x x61 x3对应对应arcsinx xx - arctan x61 x3、利用泰勒公式- o (x2sin x = x3x- o3!cos x = 1(x2)2In (1+ x ) = x -2+ o(x2)22,n! 5 + I)!r 5!+(-ir+心工xCOS JV -1 2!ln(l + x) = x- -2-=+ .r+.r+况 Jr, m(wi - h q(1 + jr) = 1 + rnx +JT +