Sunday

April 20, 2014

April 20, 2014

Posted by **purple1** on Saturday, March 20, 2010 at 8:14pm.

9-3+1-1/3+1/9...

1/2+1+2+4...

- math -
**Reiny**, Saturday, March 20, 2010 at 8:40pmS

_{∞}= a/(1/r) where │r│ < 1

in the first,

a = 9, r = -1/3

so sum = 9/(1 - (-1/3)) = 6.75 or 27/4

For the second one, there is no sum, since the series diverges.

notice r = 2, so it does not satisfy the condition for the formula.

- math -
**purple1**, Saturday, March 20, 2010 at 8:44pmThank you.

- typo - math -
**Reiny**, Saturday, March 20, 2010 at 8:49pmI just notice a typo in my formula, should of course be

a/(1-r) where │r│ < 1

I did use it correctly in the calculations

**Related Questions**

Calculus - The problem I have is a summation from 1 to infinity for (-1)^n/n. I ...

sum geometric series - what is the sum of geometric infinite series 3/2+ 9/16+ ...

Math 12th grade - Find the sum of each infinite series, or state that the sum ...

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 - find the sum of the series: 1. the sum from n=1 to infinity of ((-1)^...

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

calculus - Find the sum of the series (-1)^n (5^(2n))/n! 1. sum = e^25 2. sum = ...

math URGENT!!!! - i have a list of 5 different numbers. the sum of 2 of the ...