Evaluate sum _(i=1)^n(i^2+1)= ) - (2n^3+3n^2+7n)/(6) (2n^3+3n^2+7)/(6) (3n^3+2n^2+7n)/(6) infty (5n^3+7n)/(6)

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Answer 1

## Step 1: Expand the Summation### The summation can be split into two separate sums: the sum of

and the sum of 1. This allows us to utilize known summation formulas.## Step 2: Apply Summation Formulas### We know that

and

. Substituting these formulas into the expanded summation yields

.## Step 3: Simplify the Expression### Expanding and simplifying the expression

gives us

.

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