How do I do exponential regression in the form y=ab^x?
Casio graphing calculators do exponential regression in the form y=ae^bx. Some other calculators (for example, Texas Instruments) use y=ab^x instead. Some information on what to do can be seen here: http://www.casiocalc.org/?showtopic=3234 Start by performing the exponential regression on the Casio calculator. You will be given values for a and b that fit into y=ae^bx. I recommend that you write down these values. The b value in y=ab^x is different than the b value in y=ae^bx. To avoid confusion, the Web link mentioned above uses an uppercase B for the y=aB^x equation. We will do the same for the remainder of this procedure. Let us examine the equation: y=ae^bx We know that e^(bx) is equal to (e^b)^x because of one of the rules of powers. Therefore, this equation can be rewritten as: y=a(e^b)^x We are looking for the form: y=aB^x By comparing the last two equations, we can see that B=e^b. Therefore, to find the B value for y=aB^x, simply calculate e^b using the b value you got from y=a
