Derivatives F4003F
1. **Problem Statement:** Given the function $$f(x) = \frac{x^2 - 2}{x^4}$$, find its first derivative $$f'(x)$$ and second derivative $$f''(x)$$.
2. **Rewrite the function:** To differentiate easily, rewrite $$f(x)$$ as
$$f(x) = (x^2 - 2) x^{-4} = x^{2-4} - 2x^{-4} = x^{-2} - 2x^{-4}$$.
3. **First derivative:** Use the power rule $$\frac{d}{dx} x^n = n x^{n-1}$$.
$$f'(x) = \frac{d}{dx} (x^{-2}) - 2 \frac{d}{dx} (x^{-4}) = -2 x^{-3} - 2(-4) x^{-5} = -2 x^{-3} + 8 x^{-5}$$.
4. **Simplify first derivative:**
$$f'(x) = -\frac{2}{x^3} + \frac{8}{x^5}$$.
5. **Second derivative:** Differentiate $$f'(x)$$ again:
$$f''(x) = \frac{d}{dx} \left(-2 x^{-3} + 8 x^{-5} \right) = -2(-3) x^{-4} + 8(-5) x^{-6} = 6 x^{-4} - 40 x^{-6}$$.
6. **Simplify second derivative:**
$$f''(x) = \frac{6}{x^4} - \frac{40}{x^6}$$.
**Final answers:**
$$f'(x) = -\frac{2}{x^3} + \frac{8}{x^5}$$
$$f''(x) = \frac{6}{x^4} - \frac{40}{x^6}$$