Science:Math Exam Resources/Courses/MATH105/April 2012/Question 03 (a)
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Question 03 (a) 

Compute the following indefinite integral: 
Make sure you understand the problem fully: What is the question asking you to do? Are there specific conditions or constraints that you should take note of? How will you know if your answer is correct from your work only? Can you rephrase the question in your own words in a way that makes sense to you? 
If you are stuck, check the hints below. Read the first one and consider it for a while. Does it give you a new idea on how to approach the problem? If so, try it! If after a while you are still stuck, go for the next hint. 
Hint 1 

Start with the substitution u = ln x. 
Hint 2 

Next, do integration by parts twice to solve for the integral you wound up with after the substitution. 
Checking a solution serves two purposes: helping you if, after having used all the hints, you still are stuck on the problem; or if you have solved the problem and would like to check your work.

Solution 

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Please rate my easiness! It's quick and helps everyone guide their studies. The integral will become less complicated if we make a substitution . First substitutionIf then . We would like to express in terms of and . Isolating gives . Solving for in gives and hence . Therefore,
First integration by partsTo find this integral, we will need to integrate by parts twice. Let and . Then and . Thus, Second integration by partsWe repeat the process on the second integral. This time, we let and . Thus, and . Now we find: Inspect the resultWe recognize the integral above as and we can now solve for : so Then We added the arbitrary constant because we are computing an indefinite integral. Bring x backFinally, the integral we desire can be found by replacing by so that : 