Function Difference Derivative
1. **State the problem:** Given the function $$f(x) = \frac{1}{\sqrt{3x^3}}$$, find expressions for:
2.1.1 $$f(x+h)$$
2.1.2 $$f(x+h) - f(x)$$
2.1.3 $$\frac{f(x+h) - f(x)}{h}$$
2.1.4 $$\lim_{h \to 0} \frac{f(x+h) - f(x)}{h}$$ (the derivative)
2. **Find $$f(x+h)$$:**
$$f(x+h) = \frac{1}{\sqrt{3(x+h)^3}} = \frac{1}{\sqrt{3(x+h)^3}}$$
3. **Calculate $$f(x+h) - f(x)$$:**
$$f(x+h) - f(x) = \frac{1}{\sqrt{3(x+h)^3}} - \frac{1}{\sqrt{3x^3}}$$
4. **Find the difference quotient $$\frac{f(x+h) - f(x)}{h}$$:**
$$\frac{f(x+h) - f(x)}{h} = \frac{1}{h} \left(\frac{1}{\sqrt{3(x+h)^3}} - \frac{1}{\sqrt{3x^3}}\right)$$
5. **Find the limit as $$h \to 0$$:** This is the derivative of $$f(x)$$.
Rewrite $$f(x)$$ to a power form to differentiate easily:
$$f(x) = (3x^3)^{-1/2} = 3^{-1/2} x^{-3/2}$$
Using the power rule:
$$f'(x) = 3^{-1/2} \cdot \left(-\frac{3}{2}\right) x^{-5/2} = -\frac{3}{2 \sqrt{3}} x^{-5/2} = -\frac{3}{2 \sqrt{3} x^{5/2}}$$
**Final answers:**
1. $$f(x+h) = \frac{1}{\sqrt{3(x+h)^3}}$$
2. $$f(x+h) - f(x) = \frac{1}{\sqrt{3(x+h)^3}} - \frac{1}{\sqrt{3x^3}}$$
3. $$\frac{f(x+h) - f(x)}{h} = \frac{1}{h} \left(\frac{1}{\sqrt{3(x+h)^3}} - \frac{1}{\sqrt{3x^3}}\right)$$
4. $$\lim_{h \to 0} \frac{f(x+h)-f(x)}{h} = -\frac{3}{2 \sqrt{3} x^{5/2}}$$