logarithms (please help)

zee

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Jan 15, 2006
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I don not know how to solve for y when there is a log only on one side of the equation. Please explain how to do this problem.



Express y in terms of x.

log y = 1.2x - 1




Thank you.
 
Don't over-think it . . .

If \(\displaystyle \mbox{ y = \log_b{x}}\)

\(\displaystyle \mbox{ }\) then \(\displaystyle \mbox{ x = b^y}\)

(You are probably expected to assume the log is base 10.)
 
Hello, zee!

Express \(\displaystyle y\) in terms of \(\displaystyle x:\;\;\log y\;=\;1.2x\,-\,1\)
\(\displaystyle \text{We must "exponentiate" both sides:} \L\;e^{^{\ln y}}\;=\;e^{^{1.2x\,-\,1}}\)


\(\displaystyle \text{Since }\L e^{^{\ln y}}\,=\,y,\,\)\(\displaystyle \text{ we have: }\L\,y\;=\;e^{^{1.2x-1}}\)
 
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