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Compute the area between the graphs of functions

Let

    \[ f(x) = x^{1/3}, \qquad g(x) = x^{1/2}. \]

Find the area between the graphs of f and g on the interval [1,2].


First, we draw the graph, shading the region S between the two graphs in blue.

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Then, we calculate the area, a(S) of S:

    \begin{align*}   a(S) = \int_1^2 (g(x) - f(x))\, dx &= \int_1^2 \left(x^{1/2} - x^{1/3}\right) \, dx \\   &= \left. \frac{2}{3}x^{3/2} \right|_1^2 - \left. \frac{3}{4}x^{4/3} \right|_1^2 \\   &= \left(\frac{4 \sqrt{2}}{3} - \frac{2}{3} \right) - \left( \frac{6 \sqrt[3]{2}}{4} - \frac{3}{4} \right) \\   &= \frac{4 \sqrt{2}}{3} - \frac{3 \sqrt[3]{2}}{2} + \frac{1}{12}. \end{align*}

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