Question 0502d

Sigma Notation

Bottom Limit Handling

Question

It is given that

{u_r = 2 r - 4}

and

\sum_{r=2}^n u_r = n^2 - 3 n + 4.

Find an expression for

\displaystyle \sum_{r=3}^{n} u_r.

in the form

{n^2 + Bn + C,}

where

{B}

and

{C}

are constants to be determined.

{B = }

{C = }