Domain Range Functions
1. Find the domain and range of each function.
2. For graphing functions 1 to 12:
- 1. $f(x,y) = y - x$
- Domain: All real numbers $x, y \in \mathbb{R}$.
- Range: All real numbers $\mathbb{R}$ since $y - x$ can be any real number.
- 2. $f(x,y) = \sqrt{y} - x$
- Domain: $y \geq 0$, $x \in \mathbb{R}$.
- Range: All real numbers because $\sqrt{y} \geq 0$ and $-x$ shifts it freely.
- 3. $f(x,y) = 4x^2 + 9y^2$
- Domain: All real $x,y$.
- Range: $f(x,y) \geq 0$, minimum 0 at $(0,0)$.
- 4. $f(x,y) = x^2 - y^2$
- Domain: All real $x,y$.
- Range: All real numbers (difference of squares can yield any value).
- 5. $f(x,y) = \frac{1}{\sqrt{16 - x^2 - y^2}}$
- Domain: $16 - x^2 - y^2 > 0$ or $x^2 + y^2 < 16$, the interior of a circle radius 4.
- Range: $(\frac{1}{4}, \infty)$ since denominator approaches 0 near boundary.
- 6. $f(x,y) = xy$
- Domain: All real $x,y$.
- Range: All real numbers.
- 7. $f(x,y) = \frac{y}{x^2}$
- Domain: $x \neq 0$, all $y$.
- Range: All real numbers.
- 8. $f(x,y) = \ln(x^2 + y^2)$
- Domain: $x^2 + y^2 > 0$ (all except origin).
- Range: $(-\infty, \infty)$.
- 9. $f(x,y) = e^{-(x^2 + y^2)}$
- Domain: All real $x,y$.
- Range: $(0,1]$, maximum 1 at $(0,0)$.
- 10. $f(x,y) = \sin^{-1}(y - x)$
- Domain: $-1 \leq y - x \leq 1$.
- Range: $[-\frac{\pi}{2}, \frac{\pi}{2}]$.
- 11. $f(x,y) = \tan^{-1}(\frac{y}{x})$
- Domain: $x \neq 0$.
- Range: $(-\frac{\pi}{2}, \frac{\pi}{2})$.
- 12. $f(x,y) = \sqrt{9 - x^2 - y^2}$
- Domain: $x^2 + y^2 \leq 9$.
- Range: $[0,3]$.
Summary of key plotting features:
- Most domains are typical like entire $\mathbb{R}^2$ or constrained by the square root or denominator.
- Ranges vary from all real numbers to bounded intervals.
Since graph plotting is requested for 1 to 12, one can plot each function in 3D to see shape:
- E.g., for $f(x,y) = y - x$ plane slanting diagonally.
- Elliptic paraboloid for $4x^2 + 9y^2$.
- Hyperbolic paraboloid like in $x^2 - y^2$.
- Circular domains for root functions.