Concepts and Vocabulary
Express the area between the graphs of \(y=x^{2}\) and \(y=\sqrt{x}\) as an integral using a partition of the \(x\)-axis. Do not find the integral.
Express the area between the graph of \(x=y^{2}\) and the line \(x=1\) as an integral using a partition of the \(y\)-axis. Do not find the integral.
Skill Building
In Problems 3–12, find the area of the region enclosed by the graphs of the given equations by partitioning the \(x\)-axis.
\(y = x, y =2x, x=1\)
\(y = x, y =3x, x=3\)
\(y=x^{2}, y=x\)
\(y=x^{2}, y=4x\)
\(y =e^{x}, y =e^{-x}, x=\ln 2\)
\(y =e^{x}, y =-x+1, x=1\)
\(y=x^{2}, y=x^{4}\)
\(y=x, y=x^{3}\)
\(y=\cos x, y=\dfrac{1}{2}, 0\leq x\leq \dfrac{\pi}{3}\)
\(y=\sin x, \ y=\dfrac{1}{2}, \dfrac{\pi}{6}\leq x\leq \dfrac{5\pi}{6}\)
In Problems 13–20, find the area of the region enclosed by the graphs of the given equations by partitioning the \(y\)-axis.
\(x=y^{2}, x=2-y\)
\(x=y^{2}, x=y+2\)
\(x=9-y^{2}, x=5\)
\(x=16-y^{2}, x=7\)
\(x=y^{2}+4, y=x-6\)
\(x=y^{2}+6, y=8-x\)
\(y=\ln x, x=1, y=2\)
\(y=\ln x, x=e, y=0\)
In Problems 21–24, find the area of the shaded region in the graph.
In Problems 25–32, find the area \(A\) of the region enclosed by the graphs of the given equations:
\(y=\sqrt{x}, y=x^{3}\)
\(y=\sqrt{x}, y=x^{2}\)
\(y=x^{2}+1, y=x+1\)
\(y=x^{2}+1, y=4x+1\)
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\(y=\sqrt{9-x}, y=\sqrt{9-3x}, x\)-axis
\(y=\sqrt{16-2x}, y=\sqrt{16-4x}, x\)-axis
\(y=\sqrt{2x-6}, y=\sqrt{x-2}, x\)-axis
\(y=\sqrt{2x-5}, y=\sqrt{4x-17}, x\)-axis
In Problems 33–46, find the area of the region enclosed by the graphs of the given equations.
\(y=4-x^{2}, y=x^{2}\)
\(y=9-x^{2}, y=x^{2}\)
\(x=y^{2}-4, x=4-y^{2}\)
\(x=y^{2}, x=16-y^{2}\)
\(y=\ln x^{2}\), the \(x\)-axis, and the line \(x=e\)
\(y=\ln x, y=1-x\), and the line \(y=1\)
\(y=\cos x, y=1-\dfrac{3}{\pi}x, x=\dfrac{\pi}{3}\)
\(y=\sin x, y=1, 0\leq x\leq \dfrac{\pi}{2}\)
\(y=e^{2x}\) and the lines \(x=1\) and \(y=1\)
\(y=e^{x}, y=e^{3x}, x=2\)
\(y^{2}=4x, 4x-3y-4=0\)
\(y^{2}=4x+1, x=y+1\)
\(y=\sin x, y=\dfrac{2x}{\pi}, x\geq 0\)
\(y=\cos x, x\geq 0, y=\dfrac{3x}{\pi}\)
Applications and Extensions
An Archimedean Result Show that the area of the shaded region in the figure is two-thirds of the area of the parallelogram ABCD. (This illustrates a result due to Archimedes concerning sectors of parabolas.)
Equal Areas Find \(h\) so that the area of the region enclosed by the graphs of \(y=x, y=8x\), and \(y=\dfrac{1}{x^{2}}\) is equal to that of an isosceles triangle of base \(1\) and height \(h\). See the figure.
Cost of Health Care The cost of health care varies from one country to another. Between 2000 and 2010, the average cost of health insurance for a family of four in the United States was modeled by \begin{equation*} A(x) =8020.6596( 1.0855^{x})\qquad 0\leq x\leq 10 \end{equation*}
where \(x=0\) corresponds to the year 2000 and \(A(x)\) is measured in U.S. dollars. During the same years, the average cost of health care in Canada was given by \begin{equation*} C(x) =4944.6424( 1.0711^{x}) \qquad 0\leq x\leq 10 \end{equation*}
where \(x=0\) corresponds to the year 2000 and \(C(x)\) is measured in U.S. dollars.
Area Find the area in the first quadrant enclosed by the graphs of \(y=\sin (2x)\) and \(y=\cos (2x), 0\leq x\leq \dfrac{\pi}{8}\).
Area Find the area of the region enclosed by the graphs of \(y=\sin ^{-1}x, y=x, 0\leq x\leq \dfrac{1}{2}\). Which axis did you choose to partition? Explain your choice.
Area
Challenge Problems
Find the area enclosed by the graph of \(y^{2}=x^{2}-x^{4}\).
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The area \(A\) of the shaded region in the figure is \(A = \dfrac{t}{2}\). Prove this as follows: