Thread: Calculus: Multiplying two power series

How do you do this accurately? I can not find the process in my book and I have hw due in less than two hours


f(x) = 5 + 3 x + 3 x^2 + 5 x^3 + ...
and
g(x) = 3 + 2 x + 2 x^2 + 3 x^3 + ...


By multiplying power series, find the first few terms of the series for the product
h(x)=f(x) * g(x) = c_0+c_1 x +c_2 x^2 + c_3 x^3 + ....

I need c1,c2,c3

c1 is 5*2x+3*3x... trying to figure out the rest
c2 is 5*2x^2+3*3x^2*(3x*2x)... i think i have this now
c3 is 5*3x^3+3x^2*2x+3x*2x^2+5*3x^3=42x^3 sorry for asking Q's i end up figuring out

Klicken Heir.

thanks. I'll try that approach from now on. My method seemed to be tedious at best for anything larger than the determination of the third or fourth coefficient.