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| <h3 class="section">1.8 <code>atan2</code>, <code>atan2f</code>—arc tangent of y/x</h3> |
| |
| <p><a name="index-atan2-15"></a><a name="index-atan2f-16"></a><strong>Synopsis</strong> |
| <pre class="example"> #include <math.h> |
| double atan2(double <var>y</var>,double <var>x</var>); |
| float atan2f(float <var>y</var>,float <var>x</var>); |
| |
| </pre> |
| <p><strong>Description</strong><br> |
| |
| <p><code>atan2</code> computes the inverse tangent (arc tangent) of <var>y</var>/<var>x</var>. |
| <code>atan2</code> produces the correct result even for angles near |
| pi/2 or -pi/2 |
| (that is, when <var>x</var> is near 0). |
| |
| <p><code>atan2f</code> is identical to <code>atan2</code>, save that it takes and returns |
| <code>float</code>. |
| |
| <p><br> |
| <strong>Returns</strong><br> |
| <code>atan2</code> and <code>atan2f</code> return a value in radians, in the range of |
| -pi to pi. |
| |
| <p>You can modify error handling for these functions using <code>matherr</code>. |
| |
| <p><br> |
| <strong>Portability</strong><br> |
| <code>atan2</code> is ANSI C. <code>atan2f</code> is an extension. |
| |
| <p><br> |
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