Final answer:
To rewrite a function using sigma notation on a calculator, you can use the sum function or sigma function. Input the function and specify the range of values to sum.
Step-by-step explanation:
The function you can use on a calculator to rewrite a function using sigma notation is typically called a sum function or sigma function. On a TI-83, 83+, or 84 calculator, this function is represented by the SUM key.
To rewrite a function using sigma notation, you would input the function and specify the range of values to sum. For example, if you have the function f(x) = 3x^2 and you want to sum it from x = 1 to x = 5, you would input SUM(3x^2, x, 1, 5).
The calculator will then calculate the sum of the function over the specified range using sigma notation.