简单计算一下即可,答案如图所示
lim(x->1) (arcsinx-sinx)/(arctanx-tanx)
=(arcsin1-sin1)/(arctan1-tan1)
是不是这样: lim(x->0) (arcsinx-sinx)/(arctanx-tanx)
x->0
arcsinx~ x+ (1/6)x^3
sinx ~ x- (1/6)x^3
arcsinx - sinx ~ (1/3)x^3
-------------
arctanx~ x- (1/3)x^3
tanx ~ x+ (1/3)x^3
arctan - tanx ~ -(2/3)x^3
--------
lim(x->0) (arcsinx-sinx)/(arctanx-tanx)
= lim(x->0) (1/3)x^3/((-2/3)x^3)
=-1/2