1. Problem: Find the derivatives of the given functions.
2. Recall the power rule for derivatives: $$\frac{d}{dx} x^n = n x^{n-1}$$ and the derivative of a constant is 0.
3. a) For $$f(x) = x^6 + 2x - 1$$
$$f'(x) = \frac{d}{dx} x^6 + \frac{d}{dx} 2x - \frac{d}{dx} 1 = 6x^5 + 2 - 0 = 6x^5 + 2$$
4. b) For $$h(x) = \frac{3}{5} x^5 - 4x^{-2}$$
$$h'(x) = \frac{3}{5} \cdot 5 x^{4} - 4 \cdot (-2) x^{-3} = 3 x^{4} + 8 x^{-3}$$
5. c) For $$f(t) = \sqrt{t} + \frac{1}{t^3} = t^{\frac{1}{2}} + t^{-3}$$
$$f'(t) = \frac{1}{2} t^{-\frac{1}{2}} - 3 t^{-4} = \frac{1}{2} t^{-\frac{1}{2}} - 3 t^{-4}$$
6. d) For $$f(x) = x^{x+1} + \frac{1}{x}$$
Use logarithmic differentiation for $$x^{x+1}$$:
Let $$y = x^{x+1}$$, then $$\ln y = (x+1) \ln x$$
Differentiate both sides:
$$\frac{1}{y} y' = \ln x + (x+1) \frac{1}{x} = \ln x + 1 + \frac{1}{x}$$
Multiply both sides by $$y$$:
$$y' = x^{x+1} \left( \ln x + 1 + \frac{1}{x} \right)$$
Derivative of $$\frac{1}{x}$$ is $$-x^{-2}$$.
So,
$$f'(x) = x^{x+1} \left( \ln x + 1 + \frac{1}{x} \right) - x^{-2}$$
Function Derivatives 64Eed4
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