1.$当k\to\infty时,x-tanx与x^k为同阶无穷小,k=（ ）$$$A.1\ B.2\ C.3\ D.4$$2.$y=xsinx+cosx的拐点（ ）$$$A.(0,2)\ B.(\pi,-2)\ C.(\frac{\pi}{2},\frac{\pi}{2...

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