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same differentiation question but using different methods watch

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    There's a differentiation question that requires you to solve y=\frac{e^x}{x}. You can see straight away that the quotient rule should be used but I decided to rewrite the equation as y=x^{-1}{e^x} and used the product rule to solve it.

    answer using product rule: \frac{-e^x}{x^2} + \frac{e^x}{x}

    using quotient rule: \frac{e^x(x-1)}{x^2}

    The answers came out totally different..(or are they in fact the same answers written differently?!)....but i thought i remembered that it's fine to rewrite the equation and solve it with the product rule......is it really not allowed to do something like this?


    They're the same (multiply the right hand fraction by x/x and combine)
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Updated: January 18, 2010

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