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

Explanation

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

### Step 1: Rewrite the equation using the Pythagorean identity
We know that \( \cos^2 \theta = 1 - \sin^2 \theta \). We can substitute this into the equation:

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