Solution 3.1:5b
From Förberedande kurs i matematik 1
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- | {{ | + | In order to eliminate <math>\sqrt[3]{7} = 7^{1/3}</math> from the denominator, we can multiply the top and bottom of the fraction by <math>7^{2/3}</math>. The denominator becomes <math>7^{1/3}\cdot 7^{2/3} = 7^{1/3+2/3} = 7^1 = 7</math> and we get |
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- | {{ | + | {{Displayed math||<math>\frac{1}{\sqrt[3]{7}} = \frac{1}{7^{1/3}} = \frac{1}{7^{1/3}}\cdot \frac{7^{2/3}}{7^{2/3}} = \frac{7^{2/3}}{7}\,\textrm{.}</math>}} |
Current revision
In order to eliminate \displaystyle \sqrt[3]{7} = 7^{1/3} from the denominator, we can multiply the top and bottom of the fraction by \displaystyle 7^{2/3}. The denominator becomes \displaystyle 7^{1/3}\cdot 7^{2/3} = 7^{1/3+2/3} = 7^1 = 7 and we get
\displaystyle \frac{1}{\sqrt[3]{7}} = \frac{1}{7^{1/3}} = \frac{1}{7^{1/3}}\cdot \frac{7^{2/3}}{7^{2/3}} = \frac{7^{2/3}}{7}\,\textrm{.} |