Is this integral substitution approach correct for evaluating the integral I?

  • Context: MHB 
  • Thread starter Thread starter karush
  • Start date Start date
  • Tags Tags
    Integral Substitution
Click For Summary
SUMMARY

The integral evaluation using substitution is confirmed correct. The integral \( I = \int_{2}^{6}\frac{y}{\sqrt{y-2}} \,dy \) simplifies to \( I = \int_{0}^{4}\frac{u+2}{\sqrt{u}} \, du \) by substituting \( u = y - 2 \). The final result of the evaluation is \( I = \frac{40}{3} \), achieved through the integration of \( u^{1/2} \) and \( u^{-1/2} \). The calculations and back substitution validate the correctness of the approach.

PREREQUISITES
  • Understanding of integral calculus
  • Familiarity with substitution methods in integration
  • Knowledge of evaluating definite integrals
  • Proficiency in manipulating algebraic expressions
NEXT STEPS
  • Study advanced techniques in integral calculus
  • Learn about improper integrals and their evaluations
  • Explore numerical integration methods for complex functions
  • Investigate the use of integration by parts for different integral forms
USEFUL FOR

Students and professionals in mathematics, particularly those focusing on calculus, as well as educators seeking to enhance their teaching methods in integral evaluation.

karush
Gold Member
MHB
Messages
3,240
Reaction score
5
$\large{S6.7.r.44}$
$$\displaystyle
I=\int_{2}^{6}\frac{y}{\sqrt{y-2}} \,dy = \frac{40}{3}$$
$$
\begin{align}
u&=y-2 &y&=u+2 \\
du&=dy
\end{align}$$
then
$$\displaystyle
I=\int_{0}^{4}\frac{u+2}{\sqrt{u}} \, du
=\int_{0}^{4}{u}^{1/2} \, du + 2\int_{0}^{4} {u}^{-1/2} \, du$$
Just seeing if going in right direction...
 
Last edited:
Physics news on Phys.org
Looks good.
 
$\large{S6.7.r.44}$
$$\displaystyle
I=\int_{2}^{6}\frac{y}{\sqrt{y-2}} \,dy = \frac{40}{3}$$
$$
\begin{align}
u&=y-2 &y&=u+2 \\
du&=dy
\end{align}$$
then
$$\displaystyle
I=\int_{0}^{4}\frac{u+2}{\sqrt{u}} \, du
=\int_{0}^{4}{u}^{1/2} \, du
+ 2\int_{0}^{4} {u}^{-1/2} \, du
=\frac{ \sqrt{2}u(u+4)}{4 } \\
\text{back subst and calc gives} \\
I=\frac{40}{3}$$
 
Last edited:

Similar threads

  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
952
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K