Saturday, October 18, 2008

Exponential Functions

Recently, we've been talking about exponential functions. We examined various exponential functions to determine which ones have the "proportionality property".

How did we determine if an equation had the proportionality property? What did we have to do?

We finally came to the conclusion that functions in the following form would have characteristics of the proportionality property:

f ( x ) = AB cx

where A, B and C are constants

This happens to be the general form for exponential functions.

Do you think there are limitations on the values of A, B, or C? Can they be decimals? Negative numbers? Equal to zero? Here is an applet that could help you answer these questions -- be patient, it takes a while to load.

Since we are examining exponential functions, here is a great tutorial and goes really well with "A Basis For Disguise", the classwork that we worked on Friday.

7 x= 5 ?

Can you write a general rule for writing 7 x as a power of 5?

Here are some YouTube videos demonstrating how to solve exponential equations.





3 comments:

Anonymous said...

Today's homework, Find That Base!, is pretty much ridiculous, so I looked some stuff up and found this website to be very helpful...

http://chickscope.beckman.uiuc.edu/explore/eggmath/expon/numbere.html

It's kinda hard to understand, but hopefully you can follow it to a certain extent. I don't know how we were supposed to figure this out on our own...

Lydia Wolkiewicz said...

http://www.youtube.com/user/patrickJMT


This guy posted over 200 videos with help in pre calc, calc, trig, etc on youtube

they're very helpful for anyone who needs extra help.

Mr. Marti said...

Lydia,

Good find. It looks like he has a couple of videos on finding an exponential equation and on logarithms.