# Power and Taylor series

Interval of Convergence of a power series

a. Consider the Power series

sum of series from n=1 to infinity of FnX^n.

Use the ratio test to determine the open interval on which the pwr series converges.

b. Show that the Taylor series of the Fcn f(x) = x/(1-x-x^2) about x=0 is given by:

x/(1-x-x^2) = sum of series at n=1 to infinity of FnX^n,

where Fn is the Fibonnaci sequence.

Hint: CAll H(x) the sum of the series of FnXn on the interval of convergence found in part (a). i.e.,

set H(x) = sum of series at n=1 to infinity of FnX^n. By keeping in mind Fn+1=Fn + Fn-1 for n=2,3,4.., compute (1+x)H(x) and then find the value of x(1+x)H(x).

https://brainmass.com/math/real-analysis/power-taylor-series-10316

#### Solution Preview

1. The ratio test said if , then is absolutely convergent (and hence convergent). In this case, we have to determine which range of x such that Let's ...

#### Solution Summary

This shows how to use the ratio test to determine when the power series converges, and complete a proof regarding the Taylor series that involves the Fibonacci sequence.