Evaluate $\sum\limits_{k = 1}^{11} {\left( {2 + {3^k}} \right)} $

Vedclass pdf generator app on play store
Vedclass iOS app on app store
We need to evaluate the sum $\sum\limits_{k = 1}^{11} {\left( {2 + {3^k}} \right)}$.
Using the linearity property of summation,we have:
$\sum\limits_{k = 1}^{11} {\left( {2 + {3^k}} \right) = } \sum\limits_{k = 1}^{11} {2 + } \sum\limits_{k = 1}^{11} {{3^k}} = 2 \times 11 + \sum\limits_{k = 1}^{11} {{3^k}} = 22 + \sum\limits_{k = 1}^{11} {{3^k}} \quad \dots (1)$
The sum $\sum\limits_{k = 1}^{11} {{3^k}}$ is a geometric series with first term $a = 3$,common ratio $r = 3$,and number of terms $n = 11$.
The sum of a geometric series is given by $S_n = \frac{a(r^n - 1)}{r - 1}$.
Substituting the values,we get:
$S_{11} = \frac{3(3^{11} - 1)}{3 - 1} = \frac{3}{2}(3^{11} - 1)$.
Substituting this back into equation $(1)$:
$\sum\limits_{k = 1}^{11} {\left( {2 + {3^k}} \right) = 22 + \frac{3}{2}(3^{11} - 1)}$.

Explore More

Similar Questions

If $1 + \cos \alpha + \cos^2 \alpha + \dots \infty = 2 - \sqrt{2}$,then $\alpha$ $(0 < \alpha < \pi)$ is

Which term of the following sequence: $2, 2\sqrt{2}, 4, \ldots$ is $128$ (in $^{\text{th}}$)?

In a $G.P.$, if the product of the first three terms is $27$ and the set of all possible values for the sum of its first three terms is $\mathbb{R} - (a, b)$, then $a^{2} + b^{2}$ is equal to . . . . . . .

If $x, y, z$ are in geometric progression and $a^x = b^y = c^z$,then . . . . . .

Difficult
View Solution

The $4^{\text{th}}$ term of a $GP$ is $500$ and its common ratio is $\frac{1}{m}$,where $m \in N$. Let $S_n$ denote the sum of the first $n$ terms of this $GP$. If $S_6 > S_5+1$ and $S_7 < S_6+\frac{1}{2}$,then the number of possible values of $m$ is $..........$

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo