Science:Math Exam Resources/Courses/MATH105/April 2010/Question 01 (g)
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Question 01 (g) 

Let m be a positive number. If the volume of the solid of revolution generated by revolving about the xaxis the region under the graph of from x = 0 to x = m is , find the positive number m. 
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 hint below. Consider it for a while. Does it give you a new idea on how to approach the problem? If so, try it! 
Hint 

Do you remember the disc method? 
Checking a solution serves two purposes: helping you if, after having used the hint, 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. Using the disc method of integration, we know that the volume of the solid can be expressed as follows: We want the value of such that the volume is equal to , so we solve the equation: Taking the positive solution gives us our answer: . 