Natural Logs.

WTF?

Junior Member
Joined
Sep 16, 2005
Messages
95
I have quick question.

e^(x-1) = 25


I try to set it up as:

x-1 ln = ln25

Where to from there? :?
 
Hello, WTF?

You're almost there . . .

\(\displaystyle e^{x-1}\; =\; 25\)

I try to set it up as: \(\displaystyle \,(x-1)\ln(e)\:=\:\ln(25)\)
Where to from there? \(\displaystyle \;\) . . . solve for x
It may be clearer if you include all the steps . . .

We have: \(\displaystyle \,e^{^{x-1}}\:=\:25\)

Take logs: \(\displaystyle \,\ln(e^{^{x-1}})\:=\;\ln(25)\)

Then: \(\displaystyle \,(x-1)\cdot\ln(e)\:=\:\ln(25)\)

Since \(\displaystyle \ln(e)\,=\,1\), we have: \(\displaystyle \,x\,-\,1\:=\:\ln(25)\;\;\Rightarrow\;\;x\:=\:\ln(25)\,+\,1\)
 
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