\right) doesn't work on LaTeX multiline equation
<p>I'm writing an equation on LaTeX and when I want to close the formula with <code>\right)</code> it doesn't work. I'll post my code here to see if anyone can help me:</p>

<pre><code>\begin{equation*}
\begin{split}
 &amp;\bigtriangledown h=\left( \frac{1}{2}\cdot \cos \left(\frac{1}{2}\cdot x\right) \cdot \cos(y) + \cos(x) \cdot \cos(y),
 \frac{-1}{2} \cdot  \cos\left(\cos \left(\frac{1}{2}\cdot y\right)\right)\cdot \\ &amp;\sin\left(\frac{1}{2} \cdot y\right) - \sin\left(\frac{1}{2}\cdot x\right) \cdot \sin(y) - \sin(x) \cdot \sin(y) \right) 
\end{split}
\end{equation*}
</code></pre>