Paul's Online Notes
Paul's Online Notes
Home / Calculus III / 3-Dimensional Space / Calculus with Vector Functions
Show General Notice Show Mobile Notice Show All Notes Hide All Notes
General Notice

I have been informed that on March 7th from 6:00am to 6:00pm Central Time Lamar University will be doing some maintenance to replace a faulty UPS component and to do this they will be completely powering down their data center.

Unfortunately, this means that the site will be down during this time. I apologize for any inconvenience this might cause.

Paul
February 18, 2026

Mobile Notice
You appear to be on a device with a "narrow" screen width (i.e. you are probably on a mobile phone). Due to the nature of the mathematics on this site it is best viewed in landscape mode. If your device is not in landscape mode many of the equations will run off the side of your device (you should be able to scroll/swipe to see them) and some of the menu items will be cut off due to the narrow screen width.

Section 12.7 : Calculus with Vector Functions

2. Evaluate the following limit.

\[\mathop {\lim }\limits_{t \to - 2} \left( {\frac{{1 - {{\bf{e}}^{t + 2}}}}{{{t^2} + t - 2}}\vec i + \vec j + \left( {{t^2} + 6t} \right)\vec k} \right)\] Show Solution

There really isn’t a lot to do here with this problem. All we need to do is take the limit of all the components of the vector.

\[\begin{align*}\mathop {\lim }\limits_{t \to - 2} \left( {\frac{{1 - {{\bf{e}}^{t + 2}}}}{{{t^2} + t - 2}}\vec i + \vec j + \left( {{t^2} + 6t} \right)\vec k} \right) & = \mathop {\lim }\limits_{t \to - 2} \frac{{1 - {{\bf{e}}^{t + 2}}}}{{{t^2} + t - 2}}\vec i + \mathop {\lim }\limits_{t \to - 2} \vec j + \mathop {\lim }\limits_{t \to - 2} \left( {{t^2} + 6t} \right)\vec k\\ & = \mathop {\lim }\limits_{t \to - 2} \frac{{ - {{\bf{e}}^{t + 2}}}}{{2t + 1}}\vec i + \mathop {\lim }\limits_{t \to - 2} \vec j + \mathop {\lim }\limits_{t \to - 2} \left( {{t^2} + 6t} \right)\vec k = \require{bbox} \bbox[2pt,border:1px solid black]{{\frac{1}{3}\vec i + \vec j - 8\vec k}}\end{align*}\]

Don’t forget L’Hospital’s Rule! We needed that for the first term.