atanh

实例

返回不同数值的反双曲正切值：

<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">atanh</span><span class="token punctuation">(</span><span class="token constant">M_PI_4</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">atanh</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">atanh</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">atanh</span><span class="token punctuation">(</span><span class="token number">1</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">atanh</span><span class="token punctuation">(</span><span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token delimiter important">?></span></span>

亲自试一试