Solve that equation : `sinmtheta+sinntheta=0.`

Explanation

To solve the equation \( \sin(m\theta) + \sin(n\theta) = 0 \), we can follow these steps:

### Step 1: Use the Sine Addition Formula
We can use the sine addition formula:
\[ \sin A + \sin B = 2 \sin\left(\frac{A + B}{2}\right) \cos\left(\frac{A - B}{2}\right) \]
In our case, let \( A = m\theta \) and \( B = n\theta \). Thus, we can rewrite the equation as:
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