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. $\frac{n}{2}(a+l)d$

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 $\frac{n}{2}(a+l)$.