Calc II Integral Homework Solving Attempts

  • Thread starter Thread starter sydneyfranke
  • Start date Start date
  • Tags Tags
    Integral
Click For Summary
SUMMARY

The forum discussion centers on solving the indefinite integral of the function (x^2 + 5x + 16)/sqrt(x^2 - 16x) using trigonometric substitution. A user initially attempted the substitution x = 4 sec(x) but encountered complications. Another participant suggested completing the square for the expression under the radical, leading to the transformation of the integral into a more manageable form involving hyperbolic functions, specifically recommending the substitution x = 8 + 8 cosh(u).

PREREQUISITES
  • Understanding of trigonometric substitution techniques
  • Familiarity with hyperbolic functions and identities
  • Knowledge of completing the square in algebra
  • Basic skills in integral calculus
NEXT STEPS
  • Study the method of trigonometric substitution in integral calculus
  • Learn about hyperbolic functions and their applications in integration
  • Practice completing the square for various polynomial expressions
  • Explore advanced integration techniques, including integration by parts and partial fractions
USEFUL FOR

Students and educators in calculus, particularly those focusing on integral calculus and trigonometric substitution methods. This discussion is beneficial for anyone seeking to enhance their problem-solving skills in advanced mathematics.

sydneyfranke
Messages
72
Reaction score
0

Homework Statement



Indefinite integral of (x^2+5x+16)/sqrt(x^2-16x)

Homework Equations



Trig substitution and identities.


The Attempt at a Solution



I've tried setting x = 4 sec x but it has turned into a mess, and I really don't know where to go now. Using x, I'm left with

(16sec^2(x)+20sec(x)+64sec(x)tan(x))/sqrt(16sec^2(x)-64sec(x))

But I'm not even sure if I've done this right. Any help would be much appreciated! Thanks!
 
Physics news on Phys.org
sydneyfranke said:

Homework Statement



Indefinite integral of (x^2+5x+16)/sqrt(x^2-16x)

Homework Equations



Trig substitution and identities.


The Attempt at a Solution



I've tried setting x = 4 sec x but it has turned into a mess, and I really don't know where to go now. Using x, I'm left with

(16sec^2(x)+20sec(x)+64sec(x)tan(x))/sqrt(16sec^2(x)-64sec(x))

But I'm not even sure if I've done this right. Any help would be much appreciated! Thanks!
You probably did your trig substitution too soon.

For the expression in the radical, complete the square to get x2 - 16x + 64 - 64. This factors into (x - 8)2 - 64, which you can turn into u2 - 82.
 
Last edited:
I would work on the denominator first, so:
[tex] \sqrt{x^{2}-16x}=\sqrt{(x-8)^{2}-64}[/tex]
and then let:
[tex] x=8+8\cosh u[/tex]
 

Similar threads

  • · Replies 22 ·
Replies
22
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
1K
Replies
10
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 27 ·
Replies
27
Views
4K