Hello.
I don't know how to calculate given coefficients in a given series. For example
coefficient next to
or a different one:
coefficient next to
Could you explain to me how it is done?
(x^3 + x^4 + ...) = x^9(1+x+x^2+...) = x^9/(1-x)^3. You can expand the denominator and use a Taylor series expansion and collect the coefficients.
You can try looking up Maclaurin series or Taylor series expansion.