Question

The sum up to $n$ terms of an AP with first term $a$, last term $l$ and common difference $d$ is:

• A. $\frac{n}{2}[2a+(n-1\left)d\right]$
• B. $n[2a+(n-1\left)d\right]$
• C. $\frac{n}{2}(a+l)$
• D. $n(2a+(n-1\left)d\right)$

Answer 1

Answer: (A), (C)

The correct options are
A $\frac{n}{2}[2a+(n-1\left)d\right]$
C $\frac{n}{2}(a+l)$

The sum up to $n$ terms of an AP with first term $a$ and common difference $d$ is $\frac{n}{2}[2a+(n-1\left)d\right]$ and the sum up to $n$ terms of an AP with first term $a$ and last term $l$ is $\frac{n}{2}(a+l)$.