- #1
qspeechc
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Homework Statement
Evaluate: [tex]\lim_{\ x \to 0^+} \frac{\ e^{-1/x}}{x}[/tex]
Homework Equations
L'Hopitals' Rule maybe? Taylor series?
The Attempt at a Solution
Before I did anything, my guess was this tends to 0, as exponentials decay faster than rational funtions.
The limits as -1/x tends to 0 from the right is [tex]-\infty[/tex]
So:
[tex]\lim_{\ x \to 0^+} \ e^{-1/x} = 0[/tex]
and ofcourse the limit of x as x tends to 0 is 0. So it is of indeterminate form 0/0
Using L'Hopital's Rule:
[tex]\lim_{\ x \to 0^+} \frac{\ e^{-1/x}}{x^2}[/tex]
And that is still of indeterminate form 0/0. In fact, you can see that using L'Hopitals Rule will always generate an indeterminate form 0/0. Taylor series are no better: after the exapansion you get
[tex]\frac{1}{x^2} +\frac{1}{2x^5} +...[/tex] or something of that nature, point is, it diverges.
Help please?