Need verification to solution for trig function limit question

kylera
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As I do not have the solution book and classes are over for the summer, I don't have any other way of verifying whether this is right or not.

Homework Statement


lim(x->0) (sin 4x) / (sin 6x)


Homework Equations





The Attempt at a Solution


If I may temporarily remove the lim sign...
\frac{sin 4x}{sin 6x} = \frac{sin4x}{4x} \times \frac{4x}{sin6x}

= \frac{sin4x}{4x} \times \frac{6x}{sin6x} \times \frac{4x}{6x}

By Limit Laws, take the limit of each fraction to get
1 \times 1 \times \frac{4}{6}

4. Final answer
2/3
 
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You could also use L'Hopital rule to get the same result.
 
Last edited:
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...

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