How to Solve Basic Integration Problems Using Substitution and Partial Fractions

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The discussion focuses on solving the integral ∫(√x)^5/((√x)^7+x^6) dx using substitution and partial fractions. The initial attempt involved taking (√x)^5 common but led to complications with substitutions. A suggested substitution of t = √x simplifies the integral, allowing for the use of partial fractions to evaluate it. Participants emphasize that substitution and partial fractions are standard methods for tackling such integrals. Ultimately, the original poster successfully solved the integral after applying the recommended techniques.
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Homework Statement


∫(√x)^5/((√x)^7+x^6) dx

Homework Equations


I have learned integration through substitution, trigonometric identities and standard integrals

The Attempt at a Solution


I took (√x)^5 common which gave 1/(x+√x^7), Then I tried to substitute √x=t, √x^7=t but it just seems to complicate things more, I don't see any fruitful trigonometric substitutions either- would be grateful if someone can tell me how to proceed
 
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Krushnaraj Pandya said:

Homework Statement


∫(√x)^5/((√x)^7+x^6) dx

Homework Equations


I have learned integration through substitution, trigonometric identities and standard integrals

The Attempt at a Solution


I took (√x)^5 common which gave 1/(x+√x^7), Then I tried to substitute √x=t, √x^7=t but it just seems to complicate things more, I don't see any fruitful trigonometric substitutions either- would be grateful if someone can tell me how to proceed
Your substitution should work.
##t = x^{1/2} \Rightarrow t^2 = x \Rightarrow 2tdt = dx##
After you make the substitution, you should get an integral that you can evaluate using partial fractions.
 
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Mark44 said:
Your substitution should work.
##t = x^{1/2} \Rightarrow t^2 = x \Rightarrow 2tdt = dx##
After you make the substitution, you should get an integral that you can evaluate using partial fractions.
The exercise in my textbook is supposed to be using the concepts I mentioned under relevant equations, therefore I need to solve it using that
 
Krushnaraj Pandya said:
The exercise in my textbook is supposed to be using the concepts I mentioned under relevant equations, therefore I need to solve it using that

Mark44 IS suggesting a method on your list---substitution. After that, partial fractions are a 100% standard method, and anybody who tells you you cannot use them is doing you a dis-service. Some integrals just cannot be done in any other way (except, maybe, by finding them in some "tables of integrals" somewhere).
 
Ray Vickson said:
Mark44 IS suggesting a method on your list---substitution. After that, partial fractions are a 100% standard method, and anybody who tells you you cannot use them is doing you a dis-service. Some integrals just cannot be done in any other way (except, maybe, by finding them in some "tables of integrals" somewhere).
ohh...ok, I'll use that then and see if I can solve it
 
Ray Vickson said:
Mark44 IS suggesting a method on your list---substitution. After that, partial fractions are a 100% standard method, and anybody who tells you you cannot use them is doing you a dis-service. Some integrals just cannot be done in any other way (except, maybe, by finding them in some "tables of integrals" somewhere).
I got the correct answer. Thanks a lot!
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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