Problem

Use the laws of logarithms to expand and simplify the expression.
\[
\ln \left(\frac{e^{x}}{1+e^{x}}\right)
\]

Answer

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Answer

The expanded and simplified expression is \(\boxed{x - \ln(1+e^{x})}\)

Steps

Step 1 :Rewrite the expression as the difference of two logarithms using the property of logarithms that states the logarithm of a quotient is the difference of the logarithms: \(\ln\left(\frac{e^{x}}{1+e^{x}}\right) = \ln(e^{x}) - \ln(1+e^{x})\)

Step 2 :Use the property of logarithms that states the logarithm of a number raised to an exponent is the product of the exponent and the logarithm of the number to bring down the exponent in the first logarithm: \(\ln(e^{x}) - \ln(1+e^{x}) = x - \ln(1+e^{x})\)

Step 3 :Simplify the expression by recognizing that the natural logarithm of e is 1: \(x - \ln(1+e^{x})\)

Step 4 :The expanded and simplified expression is \(\boxed{x - \ln(1+e^{x})}\)

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