How do you solve lnx+ln(x-2)=1?

1 Answer
Feb 4, 2017

I found: x=(2+sqrt(4+4e))/2=1+sqrt(1+e)

Explanation:

We can change the sum of logs into a log of a product and write:
ln[x(x-2)]=1
use the definition of log:
x(x-2)=e^1
rearrange and solve for x:
x^2-2x-e=0
Use the Quadratic Formula:
x_(1,2)=(2+-sqrt(4+4e))/2
x_1=(2+sqrt(4+4e))/2>0 YES
x_2=(2-sqrt(4+4e))/2<0 NO