1. Problem: Find the derivatives of the given functions.
2. Recall the power rule: $$\frac{d}{dx} x^n = n x^{n-1}$$ and the derivative of $$x^x$$ using logarithmic differentiation.
---
a) $$f(x) = x^6 + 2x - 1$$
Using the power rule:
$$f'(x) = 6x^{5} + 2 - 0 = 6x^{5} + 2$$
---
b) $$h(x) = \frac{3}{5}x^{5} - 4x^{-2}$$
Derivative:
$$h'(x) = \frac{3}{5} \cdot 5 x^{4} - 4 \cdot (-2) x^{-3} = 3x^{4} + 8x^{-3}$$
Intermediate step showing cancellation:
$$h'(x) = \cancel{\frac{3}{5} \cdot 5} x^{4} + 8x^{-3} = 3x^{4} + 8x^{-3}$$
---
c) $$f(t) = \sqrt{t} + \frac{1}{t^{3}} = t^{\frac{1}{2}} + t^{-3}$$
Derivative:
$$f'(t) = \frac{1}{2} t^{-\frac{1}{2}} - 3 t^{-4} = \frac{1}{2 \sqrt{t}} - 3 t^{-4}$$
---
d) $$f(x) = x^{x} + \frac{1}{x^{x}} = x^{x} + x^{-x}$$
Use logarithmic differentiation for $$x^{x}$$:
Let $$y = x^{x}$$, then $$\ln y = x \ln x$$.
Differentiate both sides:
$$\frac{1}{y} \frac{dy}{dx} = \ln x + 1$$
So,
$$\frac{dy}{dx} = y (\ln x + 1) = x^{x} (\ln x + 1)$$
Similarly for $$x^{-x}$$:
Let $$z = x^{-x}$$, then $$\ln z = -x \ln x$$.
Differentiate:
$$\frac{1}{z} \frac{dz}{dx} = -\ln x - 1$$
So,
$$\frac{dz}{dx} = z (-\ln x - 1) = x^{-x} (-\ln x - 1)$$
Therefore,
$$f'(x) = x^{x} (\ln x + 1) + x^{-x} (-\ln x - 1)$$
---
Final answers:
a) $$f'(x) = 6x^{5} + 2$$
b) $$h'(x) = 3x^{4} + 8x^{-3}$$
c) $$f'(t) = \frac{1}{2 \sqrt{t}} - 3 t^{-4}$$
d) $$f'(x) = x^{x} (\ln x + 1) + x^{-x} (-\ln x - 1)$$
Function Derivatives 348D9E
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.