幂级数的收敛半径为().
参考答案：
解析：
本题考查的知识点为幂级数的收敛半径．
注意此处幂级数为缺项情形．
当
即x2＜2时级数绝对收敛，可知
It was quite a serious mistake, ____caused by carelessness.
A．which I think was
B．I think which was
C．which I think it was
D．I think which it was
眼睑颜面先肿，兼见面唇青紫、心悸气促、不能平卧者属于（）。
A.先天不足，肾精亏损
B.外感风邪，肺失宣降
C.脾肾阳衰，水湿泛溢
D.心肾阳衰，血行瘀阻，水气凌心
E.心阳不足，水气凌心
的收敛半径为().
即x2＜2时级数绝对收敛，可知
的收敛半径为().即x2＜2时级数绝对收敛，可知