Curve Gradient Solutions
1. **Problem statement:**
(a) Estimate the gradient of the curve $y = \frac{1}{x} + \frac{x}{2}$ at $x=2$ by drawing a tangent.
(b) Find the solutions of the equation $\frac{1}{x} - \frac{5x}{2} + 1 = 0$ by drawing a suitable line on the grid.
2. **Formula and rules:**
- The gradient of a curve at a point is the derivative $\frac{dy}{dx}$ evaluated at that point.
- To find the gradient at $x=2$, differentiate $y$ with respect to $x$.
- For part (b), rearrange the equation to find intersections with the curve or use graphical methods.
3. **Step-by-step solution:**
**(a) Gradient at $x=2$**
- Given $y = \frac{1}{x} + \frac{x}{2}$.
- Differentiate:
$$\frac{dy}{dx} = -\frac{1}{x^2} + \frac{1}{2}$$
- Evaluate at $x=2$:
$$\frac{dy}{dx}\bigg|_{x=2} = -\frac{1}{2^2} + \frac{1}{2} = -\frac{1}{4} + \frac{1}{2} = \frac{1}{4}$$
- So, the gradient at $x=2$ is $\frac{1}{4}$.
**(b) Solve $\frac{1}{x} - \frac{5x}{2} + 1 = 0$**
- Rearrange:
$$\frac{1}{x} + 1 = \frac{5x}{2}$$
- Define $y = \frac{1}{x} + \frac{x}{2}$ (the original curve).
- The equation can be rewritten as:
$$\frac{1}{x} - \frac{5x}{2} + 1 = 0 \implies \frac{1}{x} + 1 = \frac{5x}{2}$$
- Graphically, this means find $x$ where $y = \frac{1}{x} + \frac{x}{2}$ intersects the line $y = \frac{5x}{2} - 1$.
- By drawing the line $y = \frac{5x}{2} - 1$ on the grid and finding intersection points with the curve, the solutions are approximately:
- $x \approx -0.5$
- $x \approx 1$
- $x \approx 2$
4. **Summary:**
- Gradient at $x=2$ is $\frac{1}{4}$.
- Solutions to $\frac{1}{x} - \frac{5x}{2} + 1 = 0$ are approximately $x = -0.5, 1, 2$ by graphical intersection.
This completes the problem.