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Reverse arithmetic operations explained
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[[File:Reverse-power-functions.png|400px|thumb|right|Reverse power operations. The relevant subset of the function's domain, where ''x''<sup>''y''</sup> ∈ [2, 3], is outlined and hatched.]] | [[File:Reverse-power-functions.png|400px|thumb|right|Reverse power operations. The relevant subset of the function's domain, where ''x''<sup>''y''</sup> ∈ [2, 3], is outlined and hatched.]] | ||
Some arithmetic functions also provide reverse mode operations. That is inverse functions with interval constraints. For example the <code>sqrrev</code> can compute the inverse of the <code>sqr</code> function on intervals. | Some arithmetic functions also provide reverse mode operations. That is inverse functions with interval constraints. For example the <code>sqrrev</code> can compute the inverse of the <code>sqr</code> function on intervals. The syntax is <code>X = sqrrev (C, X)</code> and will compute the enclosure of all numbers ''x'' ∈ X that fulfill the constraint ''x''² ∈ C. | ||
In the following example, we compute the constraints for base and exponent of the power function <code>pow</code> as shown in the figure. | In the following example, we compute the constraints for base and exponent of the power function <code>pow</code> as shown in the figure. | ||