Exponetiation

[Robert D. Silverman]

> > I'm confused. I've been trying to figure out a quick and easy way
> > to exponetiate to a fraction (ie. x^(4.25))  and also be able to
> > figure out the power when given the base and the result.  
> 
> a^b is exp(b*ln(a)).  So, if x = a^b and you know a and x,
> 
> 	exp(b*ln(a)) = x
> 	b * ln(a) = ln(x)
> 	b = ln(x) / ln(a)

Better make sure that a,x > 0 before using this well known trick.
Bob Silverman