Finding the Base of a Logarithm
Date: 06/08/99 at 18:56:00 From: Theodora Subject: Finding the base of a logarithm Solve for x: log (base x) 0.05 = -0.5 I don't get it at all. I couldn't solve it for myself.
Date: 06/09/99 at 08:01:51 From: Doctor Jerry Subject: Re: Finding the base of a logarithm Hi Theodora, Thanks for your question. A way that works for this particular problem is: log_x(5/100) = -1/2 log_x(1/20) = -1/2 -log_x(20) = -1/2 log_x(20) = 1/2. Now, use the equivalence log_b(a) = c is the same as b^c = a: x^(1/2) = 20. Now you can figure out x. - Doctor Jerry, The Math Forum http://mathforum.org/dr.math/
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.