atan2

实例

本例计算不同的变量 x 和 y 的反正切值：

<span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token keyword">echo</span><span class="token punctuation">(</span><span class="token function">atan2</span><span class="token punctuation">(</span><span class="token number">0.50</span><span class="token punctuation">,</span><span class="token number">0.50</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">echo</span><span class="token punctuation">(</span><span class="token function">atan2</span><span class="token punctuation">(</span><span class="token operator">-</span><span class="token number">0.50</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">0.50</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">echo</span><span class="token punctuation">(</span><span class="token function">atan2</span><span class="token punctuation">(</span><span class="token number">5</span><span class="token punctuation">,</span><span class="token number">5</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">echo</span><span class="token punctuation">(</span><span class="token function">atan2</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">,</span><span class="token number">20</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">echo</span><span class="token punctuation">(</span><span class="token function">atan2</span><span class="token punctuation">(</span><span class="token operator">-</span><span class="token number">5</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">5</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">echo</span><span class="token punctuation">(</span><span class="token function">atan2</span><span class="token punctuation">(</span><span class="token operator">-</span><span class="token number">10</span><span class="token punctuation">,</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
<span class="token delimiter important">?></span></span>

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