1.

If `sum_(k=1)^(n)k=45,` find the value of `sum_(k=1)^(n)k^(3).`

Answer» Correct Answer - 2025
Given `(1+2+3+...+n)=45 rArr (1)/(2)n(n+1)=45.`
`therefore (sum_(k=1)^(n)k^(3))={(1)/(2)n(n+1)}^(2)=(45)^(2)=2025.`


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