Solving Improper Integral $\int_{-\infty}^{0}e^{-|x|}dx

  • Thread starter Thread starter KingSloth
  • Start date Start date
Click For Summary
SUMMARY

The improper integral $\int_{-\infty}^{0} e^{-|x|} dx$ simplifies to $\int_{-\infty}^{0} e^{-x} dx$ because for $x < 0$, $|x| = -x$. The correct evaluation of this integral yields a result of 1, not -1. The confusion arises from misapplying the limits and the exponential function. The integral evaluates to $e^{-x}$, and upon solving, the limit as $x$ approaches $-\infty$ results in a total area of 1 under the curve.

PREREQUISITES
  • Understanding of improper integrals
  • Knowledge of exponential functions
  • Familiarity with the properties of absolute values
  • Basic calculus skills, specifically integration techniques
NEXT STEPS
  • Study the evaluation of improper integrals in detail
  • Learn about the properties of the exponential function, particularly $e^{-x}$
  • Explore the concept of absolute values in piecewise functions
  • Practice solving similar integrals with different limits and functions
USEFUL FOR

Students studying calculus, particularly those focusing on integration techniques, and educators looking for clarification on improper integrals.

KingSloth
Messages
2
Reaction score
0

Homework Statement



[tex]$\int_{-\infty}^{0}e^{-|x|}dx[/tex]

Homework Equations



[tex]$\int_{-\infty}^{0}e^{-|x|}dx[/tex]
= [tex]$\int_{-\infty}^{0}e^{-x}dx[/tex]

according to the solution these first two steps is where i go wrong. According to solution, the integral is e^x, which I don't understand. I get e^-x and when I carry out the problem I get -1. The correct answer is 1. Please explain the simplification. thank you
 
Physics news on Phys.org
|x| is defined to be equal to x, if x >= 0, and to -x, if x < 0. Your interval over which your are integrating is the negative half of the real line.
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
Replies
7
Views
2K
Replies
1
Views
3K
Replies
6
Views
3K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 2 ·
Replies
2
Views
4K
Replies
4
Views
3K
Replies
8
Views
2K
  • · Replies 14 ·
Replies
14
Views
2K