Question

If the sum to 'n' terms of an AP is n^2 + 2n, find the 6th term of the sequence.

Answer 1

@ganeshie8 sorry

Answer 2

Consider an arithmetic progression :
\[\rm \large a_1, a_2, a_3, a_4, a_5, a_6, \ldots\]

Answer 3

if you add the first 6 terms, then subtract the sum of first 5 terms, what do you get ?

Answer 4

Say :
sum of first 6 terms is \(\rm S_6\)
sum of first 5 terms is : \(\rm S_5\)

Answer 5

can we say \[\rm S_6 - S_5 = a_6\]

?

Answer 6

uh yea

Answer 7

find the value of \(\rm S_6\), \(\rm S_5\) and plugin above

Answer 8

use the given formula to find the sums

Answer 9

\[\rm\begin{align} S_n &= n^2+2n\\~\\S_6&= ?\\~\\S_5&= ?\end{align}\]

Answer 10

s6 = 36+12 = 48
s5 = 25+10 = 35

Answer 11

ooooo its 13 right thanks

Answer 12

Excellent !