How Do You Integrate -e^(-|x|) Over All Real Numbers?

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In summary, the problem asks to find the integral of -1e-|x| between negative infinity and positive infinity. The person attempting the problem tried to integrate using laws for logarithmic equations and ended up with e-|x| between negative infinity and positive infinity. This resulted in a final answer of 0, which was not the correct answer of -2. With the help of danago, it was suggested to split the integral into two separate integrals over two separate domains and use the fact that |x| = -x when x<0 and |x|=x for x>0. By doing so, the person was able to obtain the correct answer of -2 by adding the integral of the function from 0
  • #1
Cocoabean
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1. Homework Statement and equations
Find [tex]\int[/tex] -1e-|x| between negative infinity and positive infinity.

2. The attempt at a solution

So I tried to just integrate using laws for logarithmic equations and got:
e-|x| between negative infinity and positive infinity.
Of course this leaves me with:
e-∞-e-∞ = 0
I know the answer is -2, but I am not sure how to get there. Help would be much appreciated.
 
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  • #2
Try splitting the integral into two separate integrals over two separate domains.

Use the fact that |x| = -x when x<0 and |x|=x for x>0.
 
  • #3
Thanks danago, I think i figured it out. I split the integral and added the integral of the function from 0 to infinity with -infinity to 0. The first one came out to -1 and the next came out to 1 respectively, giving me -2. I fail to see how I should have caught this before though since the function is defined at 0. I guess you could see that is symmetric and just double the integral from 0 to infinity?
 

FAQ: How Do You Integrate -e^(-|x|) Over All Real Numbers?

What is the integration of -e^(-absval(x))?

The integration of -e^(-absval(x)) is an indefinite integral that can be expressed as -e^(-absval(x)) + C, where C is a constant.

Is there a specific method for integrating -e^(-absval(x))?

Yes, there are several methods for integrating -e^(-absval(x)), including substitution, integration by parts, and partial fractions.

What is the domain of integration for -e^(-absval(x))?

The domain of integration for -e^(-absval(x)) is the entire real number line, since the absolute value function can take on any value for x.

Can -e^(-absval(x)) be integrated using a definite integral?

Yes, -e^(-absval(x)) can be integrated using a definite integral by determining the limits of integration and evaluating the indefinite integral within those limits.

What is the geometric interpretation of the integration of -e^(-absval(x))?

The integration of -e^(-absval(x)) can be interpreted geometrically as the area under the curve -e^(-absval(x)) and above the x-axis, bounded by the limits of integration.

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