# Summation

What’s the sum of the first 100 counting numbers? Where does the sum of the powers of ½ converge to? How can you visualize the Taylor series expansion for sine?

Answer these questions (and more!) with summation in Desmos. Get started with the video on the right, then dive deeper with the resources and challenges below.

To use summation, you can find sigma in the Desmos keyboard (under FUNCTIONS and then misc) or by typing "sum": If you populate the upper and lower bound, Desmos will output the summation answer. You can also put a parameter for the upper and/or lower limits. 1 out of 1 found this helpful
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• IAnthonyIsAwesome

Why can't I use a_n to represent a_0 at n=0 or any other n value?

• Anthony, just use a function a(n) instead.

My problem is that Desmos seems to quit when computing a sum without telling me that it has quit!

Edit: Nevermind, I was just being sloppy: I defined the piecewise functions I was summing over with <'s instead of <='s!

• Tharun Dev V V

I want to sum only the odd numbers.

• Jmcinroy4813

• Welbaum Nathan

hi

• Noahrockyb

Anyone know how to input "Infinity" into the calculator?

• Shaun Errichiello

Type "infinity"

• Andrea Wahl

Any chance of Desmos actually working for infinite summations?

• Jeffrey Lu

For those of you who want only odd numbers, do the sum of 2n+1 for n=1 for as many numbers as you like.

• Flexagontnt

What can the infinity symbol be used as an input?