Chapter 4: Problem 5
Use the properties of natural logarithms to simplify each function. $$ f(x)=\ln (9 x)-\ln 9 $$
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Chapter 4: Problem 5
Use the properties of natural logarithms to simplify each function. $$ f(x)=\ln (9 x)-\ln 9 $$
These are the key concepts you need to understand to accurately answer the question.
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Derive the formula $$ \log _{a} x=\frac{\ln x}{\ln a} \quad(\text { for } a>0 \text { and } x>0) $$ which expresses logarithms to \(a n y\) base \(a\) in terms of natural logarithms, as follows: a. Define \(y=\log _{a} x\), so that \(x=a^{y}\), and take the natural logarithms of both sides of the last equation and obtain \(\ln x=y \ln a\). b. Solve the last equation for \(y\) to obtain \(y=\frac{\ln x}{\ln a}\) and then use the original definition of \(y\) to obtain the stated change of base formula.
Explain why it is obvious, without any calculation, that \(\frac{d}{d x} \ln e^{x}=1\).
A recent study found that one's earnings are affected by the mathematics courses one has taken. In particular, compared to someone making $$\$ 40,000$$ who had taken no calculus, a comparable person who had taken \(x\) years of calculus would be earning \(\quad\) $$\$40,000 e^{0.195 x}$$. Find the rate of change of this function at \(x=1\) and interpret your answer.
A European oil-producing country estimates that the demand for its oil (in millions of barrels per day) is \(D(p)=3.5 e^{-0.06 p}\), where \(p\) is the price of a barrel of oil. To raise its revenues, should it raise or lower its price from its current level of $$\$ 120$$ per barrel?
For each function: a. Find the relative rate of change. b. Evaluate the relative rate of change at the given value(s) of \(t\). $$ f(t)=e^{t^{3}}, \quad t=5 $$
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