Math Help - Maclaurin series

1. Maclaurin series

When we expand maclaurin series for function y = ln(1+x) then we need the condition $-1 < x \le 1$. Why???
Pl help me. Thanks so much.

2. Originally Posted by mahefo
When we expand maclaurin series for function y = ln(1+x) then we need the condition $-1 < x \le 1$. Why???
Pl help me. Thanks so much.
First get the series. Then use the ratio test to find the interval of convergence of the series.

3. Actually, root test is faster, but it'd yield the same interval of convergence.

4. Yes, i understand. But why in the proof of Taylor series (or Maclaurin series) we don't need any conditions for x and f(x)?

5. Originally Posted by mahefo
Yes, i understand. But why in the proof of Taylor series (or Maclaurin series) we don't need any conditions for x and f(x)?
I think you'll find most statements of the Taylor Series do include something about convergence. See for example Taylor series - Wikipedia, the free encyclopedia