find the sum of the given series:

heres the equation: http://img19.imageshack.us/img19/559/untitledyc9.jpg

I was told it could be done by first finding a and b using that 2n +1 = a(n+1) + b

and given as a hint that E(n + 1)x^n is the derivateive of a known power series already.

please help me with this.

thankyou.