Expert: Sherman D. - 4/4/2009

Question
How to solve expressions of this format?

1. a= 10 log10 (x/y) , where x is known and so is a, but y is unknown. how to get rid of log term?

2. 0.01= 1-exp( a/b), simillarly, a is known b is unknown. how to get rid of the exp term?

kindly help!

Answer
1.)
a = 10 * log(base 10)(x/y)
a = 10 * (log(x/y)/log(10))
a = 10 * (log(x/y)/1)
(a/10) = log(x/y)
10^(a/10) = x/y
y = x/(10^(a/10))

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2.) By this do you mean

.01 = 1^(-a/b)
ln(.01) = (-a/b)(1)
b = -a/ln(.01)
b = -a/(ln(1/100))
b = -a/(ln(1) - ln(100))
b = -a/(0 - ln(100))
b = a/ln(100)

if you meant .01 = 1 - 10^(a/b) or .01 = 1 - e^(a/b) just let me know.