122 Views

Download Presentation
## Modeling exponential growth

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -

**Modeling exponential growth**May 28, 2009**Objectives**• Use exponential functions to model exponential growth and decay**Parts of an exponential function**y=bxis the model that we discussed yesterday. When the initial value (the value at zero) isn’t one, new model is: y=a∙bx a is the initial value b is the growth rate (or decay rate)**Modeling exponential growth**• To model exponential growth, determine the original amount (a). • Then determine the percent increase. Change this into a decimal and add it to 1. This is the growth rate (b). • Plug in the number of years, months, days, etc. (x). I have 4 weasels. Their growth rate is 150% per year. How many weasels will I have after 10 years?**Try this one**A certain species of plant grows at the rate of 14% per week. If you began with 100 plants, how many will you have after 3 weeks? A month? A year?