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Express the Sum in Terms of N k=1n(k2+5k+5)\sum _ { k = 1 } ^ { n } \left( k ^ { 2 } + 5 k + 5 \right)

Question 11

Multiple Choice

Express the sum in terms of n. k=1n(k2+5k+5) \sum _ { k = 1 } ^ { n } \left( k ^ { 2 } + 5 k + 5 \right) (Hint: Use the theorem on sums to write the sum as k=1nk2+5k=1nk+k=1n5\sum _ { k = 1 } ^ { n } k ^ { 2 } + 5 \sum _ { k = 1 } ^ { n } k + \sum _ { k = 1 } ^ { n } 5 . Next, use the following formulas 12+22+32++n2=n(n+1) (2n+1) 61+2+3++n=n(n+1) 2\begin{array} { l } 1 ^ { 2 } + 2 ^ { 2 } + 3 ^ { 2 } + \ldots + n ^ { 2 } = \frac { n ( n + 1 ) ( 2 n + 1 ) } { 6 } \\1 + 2 + 3 + \ldots + n = \frac { n ( n + 1 ) } { 2 }\end{array} and the theorem on the sum of a constant.)


A) n39n2+23n3\frac { n ^ { 3 } - 9 n ^ { 2 } + 23 n } { 3 }
B) n3+9n223n3\frac { n ^ { 3 } + 9 n ^ { 2 } - 23 n } { 3 }
C) n3+9n2+23n3\frac { n ^ { 3 } + 9 n ^ { 2 } + 23 n } { 3 }
D) n39n223n3\frac { n ^ { 3 } - 9 n ^ { 2 } - 23 n } { 3 }
E) n3+3n2+46n3\frac { n ^ { 3 } + 3 n ^ { 2 } + 46 n } { 3 }

Correct Answer:

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