How can we approximate the real number solution s to the polynomial function f(x) = x³ – 2x² + 5x – 6?

To approximate the real number solution s to the polynomial function f(x) = x³ – 2x² + 5x – 6, we can use several methods, with one of the most straightforward being the Newton-Raphson method or a graphical approach.

Step 1: Identify the Function

First, let’s define the polynomial. The function is:

f(x) = x³ – 2x² + 5x – 6

Step 2: Graphical Representation

To get a rough idea of where the real solutions lie, we can plot the function. A simple graph will show where the curve intersects the x-axis, which indicates the real roots of the polynomial. You can use tools like Desmos or a graphing calculator to visualize this.

Step 3: Apply the Newton-Raphson Method

If we want a more precise approximation, we can apply the Newton-Raphson method:

  1. Choose an initial guess (x0): Based on the graphical output, you might start with an initial guess close to where you see the curve hitting the x-axis. Let’s say we choose x0 = 2.
  2. Calculate f(x0) and f’(x0): You need the first derivative of the function, f'(x) = 3x² – 4x + 5.
  3. Iterate: Use the formula for the Newton-Raphson method:

    x1 = x0 – (f(x0) / f’(x0))

    Repeat this process until you reach a sufficiently accurate approximation. For example, if you plug in values, you will get:

    • First iteration with x0 = 2 might yield x1 ≈ 2.2.
    • Next, calculate for x1 = 2.2 and repeat.

Step 4: Check Convergence

Continue iterating until f(x) is within a small tolerance around zero. This will lead you closer to the actual real root of the polynomial.

Using this method, you’ll be able to approximate the real solution s for the polynomial function f(x).

Conclusion

In summary, to approximate the real number solution s for the polynomial function, you can use graphical methods for an initial guess followed by the Newton-Raphson method for more precision. This approach effectively balances the technical and engaging aspects of finding roots in polynomial equations.

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