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avatar+386 

I have k,b and e > 0

 

log base b (k)= 2,5 and log base e (b) = 2

 

I have to find log base e (k) = ?

 

I tried this:

 

log base b (k)= log k/log b = 2,5/1

 

log base e (b) = log b/ log e = 2/1

 

If log base b (k)=2,5 then k=b^2,5

If log base e (b)=2 then    b=e^2         Which means k= (e^2)^2,5=e^5

 

So now we have k= e^5 and b= e^2

 

 

log base e (k) = log base e (e^5) = log e^5 / log e = log e^4 = (approx) 1,73717

 

Am I right?

 Aug 2, 2016

Best Answer 

 #2
avatar+386 
+5

Daaaamn never thought about the log base e (e)= 1 thing. So obvious.

 

Thanks a huge lot CPhill, you're helping me a lot. 

 Aug 3, 2016
 #1
avatar+129840 
+5

logb k  = 2.5       means that  b^2.5  = k

 

loge b = 2         means that e^2  = b

 

So  this means that   b^2.5  = k  →   (e^2)^2.5  = k   →   e^5  = k

 

So 

 

loge k   = loge e^5   =    5 loge e  =  5 * 1    =  5

 

 

cool cool cool

 Aug 2, 2016
 #2
avatar+386 
+5
Best Answer

Daaaamn never thought about the log base e (e)= 1 thing. So obvious.

 

Thanks a huge lot CPhill, you're helping me a lot. 

TonyDrummer2  Aug 3, 2016

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