Calculators Log key for ti-89

There isn't a nice key for base 10 logs. Use the change of base formula, using natural logs.

[tex]\log_{a}b=c[/tex]

[tex]a^c=b[/tex]

[tex]c=\frac{\ln b}{\ln a}[/tex]

EDIT: Sorry, you wanted to program a hotkey. I'm not familiar with how to do that, but I'm sure it's in the manual.

 

if you want to use this function in calculations, a program isn't very helpful. I would suggest a user defined function. first,let me mention that I think log is in catalog, maybe you can move it to your custom menu. Anyways, what I do, is make a function that does the log base anything of anything. try this: define Logg(a,b)=ln(b)/ln(a) or you could do ln(b)/ln(a)-> Logg(a,b) (ps the '->' is the store button on your calculator. I think define is f4 or something, if you can't find it look in your catalogue)