Wednesday

November 26, 2014

November 26, 2014

Posted by **sarah** on Friday, March 21, 2008 at 1:02am.

1. the sum from n=1 to infinity of ((-1)^n*(.2)^n)/n

I simplified this to: (-.2)^n/n

I know this is alternating, but how do I know what the sum is?

2. the sum from n=0 to infinity of 1/2^n

Is this geometric with n^(-2)? and if so, do you use the formula?

3. the sum from n=1 to infinity of n/(2^(n-1))

THANK YOU SO MUCH

- calculus -
**Count Iblis**, Friday, March 21, 2008 at 11:39am1) Log[1 + x] =

sum from n = 1 to infinity of

(-1)^(n+1) x^n/n

2) 1/[1+x] = sum from n=0 to infinity of x^n

x = 1/2, there is no n^(-2) in here.

3)

Differentiate both sides of the equation:

1/[1+x] = sum from n=0 to infinity of x^n

with respect to x.

**Answer this Question**

**Related Questions**

Calculus - Determine convergence or divergence for the following series. State ...

College Calculus (Binomial Series) - Expand f(x) = (x+x^2)/((1-x)^3) as a power ...

calculus - determine whether the series is convergent if so find sum: the sum of...

calculus - test the series for convergence or divergence using the alternating ...

calculus - test the series for convergence or divergence using the alternating ...

calculus - Consider the infinite series of the form: (+/-)3(+/-)1(+/-)(1/3...

calculus - Consider the infinite series of the form: (+/-)3(+/-)1(+/-)(1/3...

Calculus - Consider the infinite series of the form: (+/-)3(+/-)1(+/-)(1/3...

calculus - determine whether the series is convergent if so find sum it is the ...

calculus - Another problem: determine whether the series is convergent if so ...