Question

lim(x趋向于无穷) 1/x^a(积分上限x^2 积分下限0)√(1+t^4)dt 存在且不为零,则常数a=?极限值是

Answer 1

把x^a 放到分母上

http://chart.googleapis.com/chart?cht=tx&chl=lim_{xtoinfty}frac{1}{x^aint_{0}^{x^2}sqrt{1%2Bt^4},dt}

然后求导

显然要求有极限存在,则-a-1=4 则a=-5