Question

for the arithmetic series below find S25
4+14+24+34+...

Answer 1

is that the 25th term

Answer 2

ok so you need the 1st term a = and common difference d = and you know the number of terms n = 25

so the formula is

\[S_{25} = \frac{n}{2}[2a + (25 - 1) \times d]\]

when you have a and d substitute and evaluate for the sum