Series: Arithmetic Progression Formula Manipulation

Worked Solution:

The formula for the sum, S of n terms of the arithmetic series starting at a whose terms have a common difference of d is:

S =	n (2 a + (n – 1) d ) 2

For this arithmetic series, we have

a =

–  5 2

,

n =

49

and

d =

–  3 2

–

–  5 2

=

1

With the values for this series we have:

S =	49 ( 2× –  5 2 + ( 49 –1) 1 ) 2

S =

2107 2

= 1053.5