Integration of (e[SUP]-√x[/SUP])/√x

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Homework Statement
Compute the integral with upper bound infinity and lower bound 1
Relevant Equations
Integral of (e[SUP]-√x[/SUP])/√x
(e-√x)/√x (integral from title)

I integrated by substituting and the bounds changed with inf changing to -inf and 1 changing to -1

My final integrated answer is -2lim[e-√x]. What happens to this equation at -inf and -1? As I can't put them into the roots
 
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I'm not sure I understand the difficulty.
 
Anne5632 said:
Homework Statement:: Compute the integral with upper bound infinity and lower bound 1
Relevant Equations:: Integral of (e-√x)/√x

(e-√x)/√x (integral from title)

I integrated by substituting and the bounds changed with inf changing to -inf and 1 changing to -1

My final integrated answer is -2lim[e-√x]. What happens to this equation at -inf and -1? As I can't put them into the roots
You have the wrong limits. \sqrt{x} is the positive root. Thus \sqrt{1} = 1 and \sqrt{+\infty} = +\infty.
 
pasmith said:
You have the wrong limits. \sqrt{x} is the positive root. Thus \sqrt{1} = 1 and \sqrt{+\infty} = +\infty.
Thank you, I originally let my substitution = -√x
But √x is better
Final answer now is 2/e
 
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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