MATLAB Answers


Sum of numeric string.

Asked by Cruise
on 30 Nov 2011

I have a mathematical function.This's a numeric string. How can i calculate sum of numeric string? Example: Sum of (1/3^n) with n from n to extend at infinity And what is symbol of infinity in matlab? Thanks.



No products are associated with this question.

2 Answers

Answer by Naz
on 30 Nov 2011

I hope you realize that computer has finite memory and can not run it forever to reach your infinity, so you gonna have to stop somewhere :). Here's what you can do:

for x=1:1000


Answer by Walter Roberson
on 30 Nov 2011

If you have the symbolic toolbox,

syms n
symsum(sym('1/3')^n, n, n, inf)

Please, though, recheck that your lower bound is really "n" just like the variable of summation. Using the same variable in both places can lead to some odd calculations. Did you perhaps mean that n should be from 1 to infinity? If so then put 1 in place of the parameter that is before infinity (the lower bound of the summation.)


on 30 Nov 2011

This is a convergent series and i want to use convergent characteristic to calculate sumation.

syms x k
s1 = symsum(1/k^2,1,inf)
s2 = symsum(x^k,k,0,inf)

when i type this code in command window.why matlab don't show me "s1"?

I do not know why that code would not show s1 . Unfortunately I cannot test it myself.

You could try

s1 = symsum(1/k^2,k,1,inf)

Join the 15-year community celebration.

Play games and win prizes!

Learn more
Discover MakerZone

MATLAB and Simulink resources for Arduino, LEGO, and Raspberry Pi

Learn more

Discover what MATLAB® can do for your career.

Opportunities for recent engineering grads.

Apply Today

MATLAB Academy

New to MATLAB?

Learn MATLAB today!