a) $$f(x) = x^3; x_0 = 1$$
- $$f(x_0) = f(1) = 1^3 = 1$$
- $$f'(x) = 3x^2$$
- $$f'(x_0) = f'(1) = 3 \cdot 1^2 = 3$$
- Уравнение касательной имеет вид: $$y = f(x_0) + f'(x_0)(x - x_0)$$
Тогда: $$y = 1 + 3(x - 1) = 1 + 3x - 3 = 3x - 2$$
Ответ: $$y = 3x - 2$$
б) $$f(x) = \frac{x^2}{4} - x; x_0 = 2$$
- $$f(x_0) = f(2) = \frac{2^2}{4} - 2 = \frac{4}{4} - 2 = 1 - 2 = -1$$
- $$f'(x) = \frac{2x}{4} - 1 = \frac{x}{2} - 1$$
- $$f'(x_0) = f'(2) = \frac{2}{2} - 1 = 1 - 1 = 0$$
- $$y = -1 + 0 \cdot (x - 2) = -1$$
Ответ: $$y = -1$$
в) $$f(x)=\sqrt{4x-x^2}; x_0 = 2$$
- $$f(x_0) = f(2) = \sqrt{4 \cdot 2 - 2^2} = \sqrt{8 - 4} = \sqrt{4} = 2$$
- $$f'(x) = \frac{1}{2\sqrt{4x-x^2}} \cdot (4 - 2x) = \frac{4 - 2x}{2\sqrt{4x-x^2}} = \frac{2 - x}{\sqrt{4x-x^2}}$$
- $$f'(x_0) = f'(2) = \frac{2 - 2}{\sqrt{4 \cdot 2 - 2^2}} = \frac{0}{2} = 0$$
- $$y = 2 + 0 \cdot (x - 2) = 2$$
Ответ: $$y = 2$$