• November 8th 2006, 07:52 PM
antz215
Hey guys any help I could get on these few questions would be amazing. Thanks!

1) Find the average rate of change of the function f(x)=e^x - e^(-x) as x goes from -3 to -1. Give an exact answer (in terms of e) and an approximate answer (rounded to the nearest thousandth.)

2) If an investment of $2000 grows to$2700 in three and a half years, with an annual interest rate that is compounded quarterly, what is the annual interest rate?

3) Sketch the graph of the function: g(x) = 2 ln x+3 (label 2 points with exact coordinates.)

4) Students in a precalculus class were given a final exam. Each month thereafter, they took an equivalent exam. The class average on the exam taken after t months is given by F(t)=82-8(ln(t+1)). a) What was the class average after 6 months? b) After a year? c) When did the class average drop below 55? (Approx. answers with values rounded to nearest thousandth.)
• November 8th 2006, 08:26 PM
ThePerfectHacker
Quote:

Originally Posted by antz215
Hey guys any help I could get on these few questions would be amazing. Thanks!

1) Find the average rate of change of the function f(x)=e^x - e^(-x) as x goes from -3 to -1. Give an exact answer (in terms of e) and an approximate answer (rounded to the nearest thousandth.)

The rate of change is,
$f'(x)$ the derivative.
The avergae value is,
$\frac{1}{-1+3}\int_{-3}^{-1} f'(x)dx$
But by fundamental theorem the integral of derivative is the original function! Thus, I did not even have to integrate that expression it return back to itself.
$\frac{1}{2}\cdot (f(-1)-f(-3))$