Sigma notation and summations

Question code: 16955

Question 0505

The sum of the first

{n}

terms of a series is given by

S_n = \frac{1}{2} n (n+1) (4 n + 11).

Find the sum from the 15th term to the 25th term (both inclusive) of the series.

Find an expression, in terms of

{n,}

for the

{n}

th term of the series.

Answer

{29040.}

{u_n = 3 n (2 n + 3).}

Question code: 16955