Evaluate: `intsqrt(9-x^2)dx`

Explanation

To evaluate the integral \(\int \sqrt{9 - x^2} \, dx\), we can use the standard formula for the integral of the square root of a difference of squares. The formula is:

\[ \int \sqrt{a^2 - x^2} \, dx = \frac{x}{2} \sqrt{a^2 - x^2} + \frac{a^2}{2} \sin^{-1}\left(\frac{x}{a}\right) + C \]

where \(C\) is the constant of integration.

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