Logarithms - I got stuck solving y= ln(x) - ln(x+2) + ln(4-x^2) for x

Cari_R

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Joined
Oct 10, 2015
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3
I have this question:

y= ln(x) - ln(x+2) + ln(4-x^2), express x in terms of y.

I have come as far as :

2x-x^2= e^y but how do I get to x= 1
±
√1-e^y ? (the answer that is given in the back of the book)


Thank you for your help!
 

Subhotosh Khan

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Staff member
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Jun 18, 2007
Messages
18,149
I have this question:

y= ln(x) - ln(x+2) + ln(4-x^2), express x in terms of y.

I have come as far as :

2x-x^2= e^y but how do I get to x= 1

√1-e^y ? (the answer that is given in the back of the book)


Thank you for your help!
2x-x^2= e^y

x^2 - 2x + e^y = 0

Now solve the quadratic equation!
 
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