Science:Math Exam Resources/Courses/MATH102/December 2013/Question B 07
• QA 1 • QA 2 • QA 3 • QA 4 • QA 5 • QA 6 • QA 7 • QA 8 • QB 1 • QB 2 • QB 3 • QB 4 • QB 5 • QB 6 • QB 7 • QB 8 • QC 1 • QC 2(a) • QC 2(b) • QC 2(c) • QC 2(d) • QC 3 • QC 4 •
Question B 07 

Initially, a patient has copies of the HIV virus. If the smallest detectable viral load is virus particles, how long (in days) will it take until the HIV infection is detectable? Assume that the number of virus particles y grows according to the equation
where t is time in days. Leave your answer in terms of logarithms. 
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 

The given differential equation satisfies exponential growth. 
Hint 2 

The solution of the differential equation is 
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 

Found a typo? Is this solution unclear? Let us know here.
Please rate my easiness! It's quick and helps everyone guide their studies. The solution of the differential equation is where in this case is the number of viral particles, is the time in days, and is some constant.
