Limit is Haunting! (1)

Calculus Level 1

lim n n 2 2 n \large{\displaystyle{\lim_{n \to \infty} \dfrac{n^2}{2^n}}} .

Find the limit above to 2 decimal places.


The answer is 0.00.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

2 solutions

Chew-Seong Cheong
Apr 13, 2017

Relevant wiki: L'Hopital's Rule - Basic

L = lim n n 2 2 n A / case, L’H o ˆ pital’s rule applies. = lim n 2 ln 2 2 2 n Differentiating up and down w.r.t. n twice = 0 \begin{aligned} L & = \lim_{n \to \infty} \frac {n^2}{2^n} & \small \color{#3D99F6} \text{A }\infty/\infty \text{ case, L'Hôpital's rule applies.} \\ & = \lim_{n \to \infty} \frac 2{\ln^2 2 \cdot 2^n} & \small \color{#3D99F6} \text{Differentiating up and down w.r.t. }n \text{ twice} \\ & = \boxed{0} \end{aligned}

Hunter Edwards
Nov 10, 2017

Create a table. (I'm not always the best with other types of solutions, so I used the easier method - not as pretty, but it works)

X | f(X)

1 | 0.5

2 | 1

3 | 1.125

4 | 1

5 | 0.781

10 | 0.098

20 | 0

50 | 0

As seen from the table, as x x \rightarrow \infty , f ( x ) 0 f(x) \rightarrow 0 .

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...