#1**0 **

From the formulas 1 + 2 + .. + n = n(n + 1)/2 and 1^2 + 2^2 + ... + n^2 = n(n + 1)(2n + 1)/6, it follows that f(k) = k^4/4 + k^3/2 + k^2/4.

Guest Feb 10, 2020

#4**+2 **

**Find \(f(k)\) such that \(\sum \limits_{k=1}^n f(k) = n^3\).**

answer see: https://web2.0calc.com/questions/math-question-please-help_11

heureka Feb 10, 2020