Solve `7cos^2theta+3sin^2theta=4`

Explanation

To solve the equation \( 7\cos^2\theta + 3\sin^2\theta = 4 \), we will follow these steps:

### Step 1: Rewrite the equation in terms of sine
We know that \( \cos^2\theta = 1 - \sin^2\theta \). We will substitute this into the equation:

\[ 7\cos^2\theta + 3\sin^2\theta = 4 \]
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