CODEWITHSUNDEEP
pythonmathsum
O.V
O.V

Reputation: 23

Translating python function to math function

I have a math expression in my head which I want to write down on paper but I'm not sure exactly how to. I know I need to use sigma but I'm not sure what the function should be. I know how to write a python code for it so I wrote that out, but I'm still not sure how to write it out as a math function. This is the code:

    def multiply_sum(integer):
        whatever = 1
        final = 0
        for i in range(1, integer + 1):
            whatever = whatever * 2
            final += whatever
        return final

Upvotes: 0

Views: 106

Answers (2)

Jacques de Hooge
Jacques de Hooge

Reputation: 7000

You could indeed compute the sum, but if you just want the notation, it is:

enter image description here

Upvotes: 0

Xilexio
Xilexio

Reputation: 1238

You're just summing 2, 4, 8, ..., 2^integer - a geometric sequence 2 * 2^i, i = 0, 1, 2... It sums up to 2^(integer+1) - 2.

You can read more about geometric series, generic formulas for the sum here and some properties here: https://en.wikipedia.org/wiki/Geometric_series.

Upvotes: 2

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