Ch. 9 - First-Order Differential Equations

Hass15th EditionThomas' CalculusISBN: 9780137616077Not the one you use?Change textbook

Hass 15th Edition

Ch. 9 - First-Order Differential Equations

Problem 9.1.24

Chapter 9, Problem 9.1.24

Use Euler’s method with dx = 1/3 to estimate y(2) if y′ = x sin y and y(0) = 1. What is the exact value of y(2)?

Verified step by step guidance

Identify the differential equation and initial condition: \(\frac{dy}{dx} = x \sin y\) with \(y(0) = 1\).

Set the step size \(\Delta x = \frac{1}{3}\) and determine the number of steps needed to reach \(x = 2\). Since \(2 \div \frac{1}{3} = 6\), you will perform 6 steps.

Apply Euler's method iteratively using the formula: \(y_{n+1} = y_n + \Delta x \cdot f(x_n, y_n)\), where \(f(x, y) = x \sin y\). Start with \(x_0 = 0\) and \(y_0 = 1\).

For each step, calculate \(y_{n+1}\) by plugging in the current values of \(x_n\) and \(y_n\) into the derivative function, then update \(x_{n+1} = x_n + \Delta x\).

To find the exact value of \(y(2)\), solve the differential equation analytically by separating variables or using an appropriate method, then apply the initial condition to find the constant of integration.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

11m

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Euler's Method

Euler's method is a numerical technique to approximate solutions of first-order differential equations. It uses a step size (dx) to incrementally estimate the value of the function by moving along the slope given by the derivative. This method is especially useful when an exact solution is difficult to find.

Solving Initial Value Problems

An initial value problem specifies the value of the unknown function at a starting point, allowing the differential equation to be solved uniquely. Here, y(0) = 1 provides the initial condition needed to apply Euler's method and to find the exact solution.

Exact Solution of Differential Equations

The exact solution involves finding an explicit formula for y in terms of x that satisfies the differential equation and initial condition. This often requires techniques like separation of variables or integrating factors, enabling comparison with numerical approximations.

Recommended video:

04:00

Solutions to Basic Differential Equations

Related Practice

Textbook Question

Integral Equations

In Exercises 7–12, write an equivalent first-order differential equation

and initial condition for y.

y = ln x + ∫ₓᵉ √ (t² + (y(t))²) dt

Textbook Question

Solve the homogeneous equations in Exercises 5–10. First put the equation in the form of a homogeneous equation.

y' = y/x + cos ((y-x)/x)

views

Textbook Question

Write the formula for a logistic function that has values between y = 0 and y = 1, crosses the line y = 1/2 at x = 0, and has slope 5 at this point.

Textbook Question

Use Euler’s method with dx = 0.2 to estimate y(1) if y′ = y and y(0) = 1. What is the exact value of y(1)?

Textbook Question

Solve the homogeneous equations in Exercises 5–10. First put the equation in the form of a homogeneous equation.

(x sin y/x - y cos y/x)dx + (x cos y/x) dy = 0

views

Textbook Question

Solve the homogeneous equations in Exercises 5–10. First put the equation in the form of a homogeneous equation.

(x.exp(y/x) + y)dx - x dy = 0

views