Why Isn't the Answer to the Hyperbolic Function e^10x?

bobsmith76
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Homework Statement




Screenshot2012-02-08at22412AM.png


why is the answer not e^10x ?

If you ignore the e's it should be

5x - 5x + 5x - - 5x, or
5x - 5x + 5x + 5x, which is 10x
 
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If you ignored the e's, it wouldn't be a hyperbolic function, but a linear function.
 
well, i still don't see any reason why the answer is not e^10x
 
Hint:

<br /> e^{x} + e^{y} \neq e^{x + y}<br />

For example: Take x = y = 0 and compare the two sides of this unequality.
 
Bob, this is basically \frac{a+b}{2} + \frac{a-b}{2} = \frac{a}{2} + \frac{b}{2} + \frac{a}{2} - \frac{b}{2} = (2)(\frac{a}{2}) = a. Simple algebra. Here a = e^{5x} and b = e^{-5x}.

But your comment indicates a deeper confusion about exponents and algebraic principles. I would suggest that it might be a good idea to review basic algebra including the rules of exponentiation.
 
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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