find the general values of '`theta`' from the following equations`cos3thetacos5theta-cos7thetacos9theta=0`

Explanation

To solve the equation \( \cos(3\theta) \cos(5\theta) - \cos(7\theta) \cos(9\theta) = 0 \), we can follow these steps:

### Step 1: Rewrite the equation using the product-to-sum identities
We know that:
\[ 2 \cos A \cos B = \cos(A + B) + \cos(A - B) \]
Thus, we can rewrite the equation as:
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