MCQ
The sum $(-6)+(0)+(6)+\ldots .$. upto $13^{\text {th }}$ term is given below :
Here, $a=-6$ and $d=0-(-6)=6$ (Step- 1$)$
$
\begin{array}{ll}
\therefore \quad & S_{13}=\frac{13}{2}[2 \times(-6)-(13-1) 6](\text { Step-2) } \\
& =\frac{13}{2}[-12+72]=\frac{13}{2} \times(60)=390(\text { Step-3) }
\end{array}
$
In which step is there an error in solving?
Here, $a=-6$ and $d=0-(-6)=6$ (Step- 1$)$
$
\begin{array}{ll}
\therefore \quad & S_{13}=\frac{13}{2}[2 \times(-6)-(13-1) 6](\text { Step-2) } \\
& =\frac{13}{2}[-12+72]=\frac{13}{2} \times(60)=390(\text { Step-3) }
\end{array}
$
In which step is there an error in solving?
- AStep-1
- ✓Step-2
- CStep-3
- DThere is no error
