Table of Contents

• Section 1. Exact Doubling Time
• 1: In search of ... the exact doubling time
• 2: Finding doubling time with messy numbers
• 3: Logs = Exponent-busters
• 4: Let's bust some exponents
• 5: More exponent busting
• Section 2. Applications
• 6: World Population
• 7: Growth of technology
• 8: Extended Problem: How long DOES poor Frank have?
• 9: Review

More exponent busting

So, give that a try on your own. Let's say we think that Frank's bloodstream was infected by a single meningicoccal cell at 3 pm, and by the next day at 3pm, he had a thriving population of about 10,000 meningicocci loose in his blood. Assuming exponential growth, how fast was the population doubling?

Start with the basic equation for exponential growth:

N_t = N₀ * 2^g

where t means the number of generations.

Here are some hints if you're not sure what to do:

 

Answers

 

You might have noticed that I haven't given you a formula to figure out the doubling time. You could write a formula based on the steps above, but it would be hard to remember, whereas if you understand logs and you follow the exponential growth equation, you WILL get the right answer. Ergo, no formula.