I just started with logarithms, and I'm pretty clueless about them. So here's one of the questions I have, and if you can explain it, I'll probably be able to figure out the rest.

NB: all the bases for these questions are x

If log 3 = 1.5, log 5 = 1.8 and log 10 = 3.0 :

evaluate log 15

which base are you using
Hi

Quote by iceman95
Fiddler is a god!!!! omg that's a good movie
in the book, the base just says x

edit: ya liek I said I'm pretty much clueless about all this
log 15 should be log 3 times 5
Edit: but ive got no idea im going off logic
Pull my finger

Quote by Explicit User

"Kyle.. Do you know what homosex is?"
me:"...yes... why?"
"Do you want to have it?"
Me again:"...no Anthony..no i don't"
"Oh.. okay.. good night"

haha

Dear god the pit is a force to be reckoned with.
cant exactly remember but i think when you multiply logs you add wat their value is together

so log3 x log 5 = 1.5 + 1.8

not exactly sure tell me if its wrong ill actually get the book out
Gear:
Maton MS503
Squier Strat
Randall RG75DG3+
Dunlop Original Crybaby
Digitech Jamman
Zoom G1

Quote by Sol9989
Caramello wins life.

Quote by A8039077
Caramello, that's mother****ing genius!
the answer for that Q is meant to be 3.3, but I don't know how to get it

edit: and ur answer is correct, cheers
if log_a b = c
then a^c = b

log_x 3 = 1.5
x^1.5 = 3
x =3^(1/1.5) =3^(2/3)

and so on for the others

if you need to work out what the base is
log15 = log(3x5) = log3 +log5

One rule of logarithms is:
log(ab) = loga +logb
The handiness of this is that what was a multiplication problem has become an addition problem.

A few others:
log(a/b) = loga - logb
log(a^r) = r x loga
That's probably all you need.
Quote by bassplayer33333
Sinisa Rules all.

Quote by zbest
That is part of the reason that the mafia does so much drug trafficing, its so they wont die of hunger because they dont have anything.
cheers for all your help people, I'll post if I need more help

Thanks