Find the area of the region enclosed by the ellipse \[ \frac{x^2}{a^2} + \frac{y^2}{b^2} = 1. \]
Step 1: The area of an ellipse with the equation \( \frac{x^2}{a^2} + \frac{y^2}{b^2} = 1 \) is given by the formula: \[ A = \pi a b. \]
Step 2: Here, \( a \) and \( b \) represent the lengths of the semi-major and semi-minor axes of the ellipse, respectively.
Step 3: Therefore, the area enclosed by the ellipse is simply: \[ A = \pi a b. \] Thus, the area of the region enclosed by the ellipse is \( \pi a b \).
Given:
\[ x \sqrt{1 + y} + y \sqrt{1 + x} + x = 0 \]for \( -1 < x < 1 \), prove that:
\[ \frac{dy}{dx} = -\frac{1}{(1+x)^2}. \]