I have general function(adsbygoogle = window.adsbygoogle || []).push({});

sum_(k=1, to n) f(k) = F(n)

ex.) sum_(k=1, to n) k = F(n)

solution: F(n) = (1+n)n/2

But If I have inverse problem?:

ex.) sum_(k=1, to n) f(k) = n^2

how to get f(k) ?

Generaly, If I have F(n), how to get f(k)

for sum_(k=1, to n) f(k) = F(n)

Is there some formula or method to solve this?

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# Sum operator

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