SOLUTION: prove that e^logx=x

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: prove that e^logx=x      Log On


   



Question 790521: prove that e^logx=x
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!

From the problem context, I am going to presume that "log" with an unspecified base is base rather than the more commonly accepted base 10. You will avoid a great deal of ambiguity in the future if you use as the natural logarithm function of meaning and reserve to mean .

We wish to prove:



Assume



And use algebra to obtain an identity.

Take the natural log of both sides:



Use the properties of logarithms:



and



to write





Which is true for all in the domain of

Therefore is true for all in the domain of .

Q.E.D.

John

Egw to Beta kai to Sigma
My calculator said it, I believe it, that settles it
The Out Campaign: Scarlet Letter of Atheism