Thread: Help expressing a function as a power series

Find the power series for (2+x)^(-3)

I'm pretty sure I'm supposed to use a binomial series, but the formula for that is (1+x)^k. Since I have (2+x)^k, all I can think of is replacing x with u = x+1, and find (1+u)^(-3). Is this correct? I'm getting stuck in the middle of the problem using this method.

Hello,

Originally Posted by paulrb

Find the power series for (2+x)^(-3)

I'm pretty sure I'm supposed to use a binomial series, but the formula for that is (1+x)^k. Since I have (2+x)^k, all I can think of is replacing x with u = x+1, and find (1+u)^(-3). Is this correct? I'm getting stuck in the middle of the problem using this method.

More simply :



So

get it ?

Ok, that makes it much easier. Thanks.