sandman@bucsb.bu.edu.UUCP (Dominick Galang) (06/18/86)
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. If anyone can help me out, please send me mail. Thanx. dg. sandman@bucsb.bu.edu
brooks@lll-crg.ARpA (Eugene D. Brooks III) (06/19/86)
In article <366@bucsb.bu.edu.UUCP> sandman@bucsb.bu.edu.UUCP (Dominick Galang) writes: >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. Try your HP calculator :-)
ark@alice.UucP (Andrew Koenig) (06/19/86)
> 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)
bs@linus.UUCP (Robert D. Silverman) (06/25/86)
> > 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