November 1, 2007

Today in PreCal 40s we had two classes. In our morning class we went over more examples of exponential equations. We learned a new technique to solve certain questions. For example we were given:

4^2x-63*4^x-64=0
(( 4^x)^2)-(63*(4^x))-64=0 Let a=4^x
a^2-63a-64=0
(a+1)(a-64)=0
4^x+1=0 4^x=64
4^x=-1 x=3
no solution


Letting the difficult exponent equal another variable is the brilliant idea we learned and it is helpful in challenging questions like this.

In the PM class we learned how to graph exponential functions and the patterns that exist. As the exponent gets bigger positively the outputs on the graph get larger and as the exponent get bigger negatively the outputs gets closer and closer to the x-axis.



The next scribe is John.