Solve the inequality $x^2 e^x - 2e^x < 0$
$
\begin{equation}
\begin{aligned}
x^2 e^x - 2e^x &< 0 \\
\\
x^2 e^x &< 2e^x && \text{Add } 2e^x\\
\\
\ln x^2 e^x &< \ln 2e^x && \text{Take ln of each side}\\
\\
\ln x^2 + \ln e^x &< \ln 2 + \ln e^x && \text{Properties of ln } \ln(AB) = \ln A + \ln B\\
\\
2 \ln x + x \ln e &< \ln 2 + x \ln e && \text{Properties of ln } \ln A^c = C\ln A\\
\\
2 \ln x &< \ln 2 && \text{Subtract } x \ln e\\
\\
\ln x &< \frac{\ln 2}{2} && \text{Divide by 2}\\
\\
e^{\ln x} &< e^{\frac{\ln 2}{2}} && \text{Raise } e \text{ to each side}\\
\\
x &< e^{\frac{\ln 2}{2}} && \text{Property of ln}
\end{aligned}
\end{equation}
$
Monday, May 18, 2015
College Algebra, Chapter 5, 5.4, Section 5.4, Problem 70
Subscribe to:
Post Comments (Atom)
Why is the fact that the Americans are helping the Russians important?
In the late author Tom Clancy’s first novel, The Hunt for Red October, the assistance rendered to the Russians by the United States is impor...
No comments:
Post a Comment