Question

将函数f(x)=1/(5-x)展开成x的幂级数,并求展开式成立的区间,快点

Answer 1

f(x)=1/(5-x)=(1/5){1/[1-(x/5)]}=(1/5){1+(x/5)+(x/5)²+···+(x/5)^n+····},成立区间(|x|