Question

The first term of an arithmetic sequence is 6 and common difference is 4. Then the algebraic expression for sum of the first 'n' terms its.

• A. $2n+4n^2$
• B. $2+4n^2$
• C. $2n^2+4n$
• D. 2+4n

Answer 1

The correct option is C

$2n^2+4n$

Algebraic expression of the sequence is

=6+(n-1)4

=6+4n-4

=2+4n

Algebraic expression of sum of n terms whose nth term is 4n+2 is $=\frac{4n(n+1)}{2}+2n$

=2n(n+1)+2n

$=2n^2+2n+2n=2n^2+4n$