Increasing Decreasing 8A9230
1. **Problem Statement:**
Find the intervals where the function $$y=\frac{x^2+4}{x^2-4}$$ is increasing or decreasing.
2. **Formula and Rules:**
To find where a function is increasing or decreasing, we find its first derivative $$y'$$ and analyze its sign.
- If $$y' > 0$$, the function is increasing.
- If $$y' < 0$$, the function is decreasing.
3. **Find the first derivative:**
Using the quotient rule:
$$y' = \frac{(2x)(x^2-4) - (x^2+4)(2x)}{(x^2-4)^2}$$
Simplify numerator:
$$= \frac{2x(x^2-4) - 2x(x^2+4)}{(x^2-4)^2} = \frac{2x x^2 - 8x - 2x x^2 - 8x}{(x^2-4)^2}$$
$$= \frac{-16x}{(x^2-4)^2}$$
4. **Analyze the sign of $$y'$$:**
- The denominator $$ (x^2-4)^2 $$ is always positive except at $$x=\pm 2$$ where the function is undefined.
- The numerator is $$-16x$$.
So:
- $$y' > 0 \Rightarrow -16x > 0 \Rightarrow x < 0$$
- $$y' < 0 \Rightarrow -16x < 0 \Rightarrow x > 0$$
5. **Intervals of increase and decrease:**
- Increasing on $$(-\infty, -2) \cup (-2, 0)$$ (excluding points where function undefined)
- Decreasing on $$(0, 2) \cup (2, \infty)$$
Note: The function is undefined at $$x=\pm 2$$, so these points split the domain.
**Final answer:**
- Increasing on $$(-\infty, -2) \cup (-2, 0)$$
- Decreasing on $$(0, 2) \cup (2, \infty)$$