Science:Math Exam Resources/Courses/MATH101/April 2008/Question 01 (e)
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Question 01 (e) 

Let and For what value of the positive constant is a probability density function? 
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 

For ƒ to be a probability density function it needs to satisfy two conditions:
Choose k such that both conditions are fulfilled. 
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. (a) Using the hint we see that, first of all, k needs to be a positive constant. We can calculate k explicitly by integrating: The only way that this integral has value 1 is when k = 12. 