What Is the Value of the Integral $\int_0^1 xe^x \, dx$?

Click For Summary
SUMMARY

The integral $\int_0^1 xe^x \, dx$ can be evaluated using integration by parts (IBP) or by substitution with $t = e^x$. The substitution leads to the transformation of the integral into $\int \ln{t} \, dt$, which still requires the use of IBP for its evaluation. The correct answer to the integral is $C. \ 2-e$.

PREREQUISITES
  • Understanding of integration techniques, specifically integration by parts (IBP).
  • Familiarity with substitution methods in calculus.
  • Knowledge of the properties of exponential functions and logarithms.
  • Basic skills in evaluating definite integrals.
NEXT STEPS
  • Study the method of integration by parts in detail.
  • Learn about substitution techniques in calculus, particularly for exponential functions.
  • Explore the properties and applications of logarithmic functions in integration.
  • Practice evaluating definite integrals involving exponential and logarithmic functions.
USEFUL FOR

Students and educators in calculus, mathematicians focusing on integration techniques, and anyone looking to deepen their understanding of evaluating integrals involving exponential and logarithmic functions.

karush
Gold Member
MHB
Messages
3,240
Reaction score
5
$\tiny{4.2.5}$

$\displaystyle\int^1_0{xe^x\ dx}$

is equal to
$A.\ \ {1}\quad B. \ \ {-1}\quad C. \ \ {2-e}\quad D.\ \ {\dfrac{e^2}{2}}\quad E.\ \ {e-1}$

$\begin{array}{lll}
\textit{IBP}
&uv-\displaystyle\int v' dv
&\tiny{(1)}\\ \\
\textit{substitution}
&u=x,\ v'=e^x
&\tiny{(2)}\\ \\
\textit{calculate}
&I=xe^x-\displaystyle\int \ e^xdx\biggr|^1_0
=xe^x-e^x\biggr|^1_0=1
&\tiny{(3)}
\end{array}$

ok I think this is ok possible typos
but curious if this could be solve not using IBP since the only variable is x
 
Physics news on Phys.org
$t=e^x \implies x = \ln{t} \implies dx = \dfrac{dt}{t}$

$\displaystyle \int xe^x \, dx = \int \ln{t} \, dt$

If you happen to know the antiderivative of $\ln{t}$ off the top of your head, great ... if not, you would need to use integration by parts anyway.
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 5 ·
Replies
5
Views
1K
Replies
4
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K