Step 1: Pick the right numerical formula.
For a function known at three equally spaced points \(x_0 - h\), \(x_0\), \(x_0 + h\), the second derivative is estimated using the central difference formula: \[ f''(x_0) \approx \frac{f(x_0+h) - 2f(x_0) + f(x_0-h)}{h^2} \]
Here \(x_0 = 0\), \(h = 0.1\), \(f(-0.1) = 2\), \(f(0) = 1\), \(f(0.1) = 2\).