Math Problem Statement

Suppose that the tangent line to the curve y = f(x) at the point (1, 13) has equation y = 9 + 4x. If Newton's method is used to locate a root of the equation f(x) = 0 and the initial approximation is x1 = 1, find the second approximation x2. Suppose that Newton's method is used to locate a root of the equation f(x) = 0 with initial approximation x1 = 7. If the second approximation is found to be x2 = -1, and the tangent line to f(x) at x = 7 passes through the point (15, 6), find f(7). Use Newton's method with initial approximation x1 = 4 to find x2, the second approximation to the root of the equation x^3 = 5x + 4.

Solution

Let's analyze the problem step by step.

Part (a) Analysis:

We are given that the tangent line to the curve y=f(x)y = f(x) at the point (1,13)(1, 13) is y=9+4xy = 9 + 4x. Using Newton's method, we are asked to locate a root of the equation f(x)=0f(x) = 0, with an initial approximation x1=1x_1 = 1. We need to find the second approximation x2x_2.

  • The equation of the tangent line gives us two key pieces of information:

    • The point (1,13)(1, 13) is on the curve, so f(1)=13f(1) = 13.
    • The slope of the tangent line is 4, so f(1)=4f'(1) = 4.

    Newton's method is defined by the recurrence relation: xn+1=xnf(xn)f(xn)x_{n+1} = x_n - \frac{f(x_n)}{f'(x_n)} Given x1=1x_1 = 1, we can calculate x2x_2.

Now I'll calculate x2x_2 using Newton's method.

Part (b) Analysis:

We are given an initial approximation x1=7x_1 = 7, and the second approximation x2=1x_2 = -1. Additionally, the tangent line at x=7x = 7 passes through the point (15,6)(15, 6). We are asked to find f(7)f(7).

Using the Newton’s method formula, we can calculate f(7)f'(7) from the given information about the tangent line and the points it passes through.

Part (c) Analysis:

We need to use Newton's method with the initial approximation x1=4x_1 = 4 to find the second approximation x2x_2 to the root of the equation x3=5x+4x^3 = 5x + 4.

I will now solve each part, starting with part (a).For part (a), the second approximation using Newton's method is x2=2.25x_2 = -2.25.

Let me proceed with the next part, part (b), to find f(7)f(7).### Part (b) Details:

We are given:

  • The initial approximation x1=7x_1 = 7
  • The second approximation x2=1x_2 = -1
  • The tangent line to f(x)f(x) at x=7x = 7 passes through the point (15,6)(15, 6).

We need to find the value of f(7)f(7). To do this, let's first determine the slope of the tangent line using the given points.

The slope of the line passing through (7,f(7))(7, f(7)) and (15,6)(15, 6) is: slope=6f(7)157\text{slope} = \frac{6 - f(7)}{15 - 7} Given that the tangent line represents the derivative at x=7x = 7, we can relate this to f(7)f'(7).

Next, we will calculate the exact value of f(7)f(7).For part (b), the value of f(7)f(7) is 52\frac{5}{2}, or 2.52.5.

Now, let's move to part (c), where we will use Newton's method to find the second approximation x2x_2 for the equation x3=5x+4x^3 = 5x + 4, with an initial approximation x1=4x_1 = 4.

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Math Problem Analysis

Mathematical Concepts

Calculus
Newton's Method
Tangent Line
Derivatives

Formulas

Newton's Method: x_{n+1} = x_n - f(x_n)/f'(x_n)
Equation of a line: y = mx + b

Theorems

Newton's Method for finding roots

Suitable Grade Level

Grades 11-12, College Level