Silversonic
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Homework Statement
Find the limit of
\frac{x^{2}cos(1/x)}{sin(x)} as x tends to 0.
It doesn't actually say with L'Hopitals rule, but up until now that's what we've been dealing with.
The Attempt at a Solution
Wolfram alpha tells me the limit is zero. I know already how to compute the limit of x^{2}cos(1/x) as x tends to 0, and this gives zero.
By L'Hopitals rule;
lim(x->0) \frac{f(x)}{g(x)} = lim(x->0) \frac{f'(x)}{g'(x)}
Can I represent lim(x->0) \frac{f(x)}{g(x)} as lim(x->0) f(x) * lim(x->0) \frac{1}{g(x)}?
And thus if I show f(x) tends to a value, and 1/g(x) tends to a value, then the whole thing tends to a value? Taking f(x) = x^{2}cos(1/x) and 1/g(x) as \frac{1}{sin(x)}, then I can compute the limit of \frac{1}{sin(x)} as the limit of \frac{e^{x}}{e^{x}sin(x)}. Using L'hopitals rule once on this gives me a limit of one. Thus the limit of the whole thing I've wanted is 0/1, so 0.
Is this correct?