Analyzing the Convergence of a McLauren Series

nns91
Messages
301
Reaction score
1

Homework Statement



Given a McLauren series: (2x)^n+1 / (n+1)

(a). Find interval of convergence.

Homework Equations



Limit test

The Attempt at a Solution



So I used ratio test and found that -1/2 <x<1/2. I am testing the end point. At x=1/2, the series will be 1/(n+1) and at x=-1/2, series is (-1)^n+1 / (n+1). How do I prove whether or not they are divergent or convergent. Does 1/ (n+1) converge to 0 ?

How about when x=-1/2, is it convergent or divergent ?
 
Physics news on Phys.org
I imagine you forgot to put the summation notation before your terms?? McLaurin series are infinite summations; anyways, 1/(n+1) converges to 0, but this is not sufficient to prove that it converges. Can you think of a fairly famous series that this reminds you of?? Similarly for the Alternating Series at x=(-1/2); although for the alternating series you could also use the alternating series test.
 
Do I compare 1/(n+1) to 1/n ??
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...

Similar threads

Replies
5
Views
2K
Replies
3
Views
1K
Replies
1
Views
1K
Replies
2
Views
2K
Replies
6
Views
2K
Replies
4
Views
1K
Replies
2
Views
1K
Back
Top