Chapter 6: Problem 1
In terms of relative growth rate, what is the defining property of exponential growth?
Chapter 6: Problem 1
In terms of relative growth rate, what is the defining property of exponential growth?
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Get started for freeThere are several ways to express the indefinite integral of sech \(x\). a. Show that \(\int \operatorname{sech} x d x=\tan ^{-1}(\sinh x)+C\) (Theorem 9 ). (Hint: Write sech \(x=\frac{1}{\cosh x}=\frac{\cosh x}{\cosh ^{2} x}=\frac{\cosh x}{1+\sinh ^{2} x},\) and then make a change of variables.) b. Show that \(\int \operatorname{sech} x d x=\sin ^{-1}(\tanh x)+C .\) (Hint: Show that sech \(x=\frac{\operatorname{sech}^{2} x}{\sqrt{1-\tanh ^{2} x}}\) and then make a change of variables.) c. Verify that \(\int \operatorname{sech} x d x=2 \tan ^{-1}\left(e^{x}\right)+C\) by proving \(\frac{d}{d x}\left(2 \tan ^{-1}\left(e^{x}\right)\right)=\operatorname{sech} x\).
Verify the following identities. \(\cosh \left(\sinh ^{-1} x\right)=\sqrt{x^{2}+1},\) for all \(x\)
For large distances from the surface of Earth, the gravitational force is given by \(F(x)=G M m /(x+R)^{2},\) where \(G=6.7 \times 10^{-11} \mathrm{N} \cdot \mathrm{m}^{2} / \mathrm{kg}^{2}\) is the gravitational constant, \(M=6 \times 10^{24} \mathrm{kg}\) is the mass of Earth, \(m\) is the mass of the object in the gravitational field, \(R=6.378 \times 10^{6} \mathrm{m}\) is the radius of Earth, and \(x \geq 0\) is the distance above the surface of Earth (in meters). a. How much work is required to launch a rocket with a mass of \(500 \mathrm{kg}\) in a vertical flight path to a height of \(2500 \mathrm{km}\) (from Earth's surface)? b. Find the work required to launch the rocket to a height of \(x\) kilometers, for \(x>0\) c. How much work is required to reach outer space \((x \rightarrow \infty) ?\) d. Equate the work in part (c) to the initial kinetic energy of the rocket, \(\frac{1}{2} m v^{2},\) to compute the escape velocity of the rocket.
Find the \(x\) -coordinate of the point(s) of inflection of \(f(x)=\operatorname{sech} x .\) Report exact answers in terms of logarithms (use Theorem 10).
Find the mass of the following thin bars with the given density function.
$$\rho(x)=\left\\{\begin{array}{ll}
x^{2} & \text { if } 0 \leq x \leq 1 \\
x(2-x) & \text { if } 1
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