xn/n在|x|<1的和函數(shù)是:()
A.ln(1-x) B.ln[1/(1-x)] C.ln(x-1) D.-ln(x-1)
/n!在(-∞,+∞)的和函數(shù)是:()
A. B. C. D.-
冪級數(shù)x2-(1/3)x3+(1/3)x4-…+[(-1)n+1/n]xn+1+…(-1()
A.xsinx B.x2/(1+x2) C.x1n(1-x) D.x1n(1+x)