Math Problem Statement

Solve the differential equation by Euler’s method to solve the initial value problem over the interval x = 0 to 2 with h = 0.5 where 2 1.1 dy yx y dx = - ; where y(0) = 1.

Solution

To solve the differential equation using Euler's method, we'll proceed step-by-step through the interval from x=0x = 0 to x=2x = 2 with a step size h=0.5h = 0.5. The differential equation given is:

dydx=21.1yx\frac{dy}{dx} = 2 - 1.1yx

with the initial condition:

y(0)=1y(0) = 1

Euler's Method

Euler's method approximates the solution to the differential equation by stepping forward from an initial point using the slope of the function. The formula for Euler's method is:

yn+1=yn+hf(xn,yn)y_{n+1} = y_n + h \cdot f(x_n, y_n)

where f(x,y)=dydx=21.1yxf(x, y) = \frac{dy}{dx} = 2 - 1.1yx.

Step-by-Step Solution

  1. Initial Condition:

    • x0=0x_0 = 0
    • y0=1y_0 = 1
  2. Step Size:

    • h=0.5h = 0.5

We will compute the values of yy at each step:

Step 1: From x=0x = 0 to x=0.5x = 0.5

f(x0,y0)=21.1y0x0=21.110=2f(x_0, y_0) = 2 - 1.1 \cdot y_0 \cdot x_0 = 2 - 1.1 \cdot 1 \cdot 0 = 2

y1=y0+hf(x0,y0)=1+0.52=1+1=2y_1 = y_0 + h \cdot f(x_0, y_0) = 1 + 0.5 \cdot 2 = 1 + 1 = 2

Step 2: From x=0.5x = 0.5 to x=1.0x = 1.0

x1=0.5,y1=2x_1 = 0.5, \quad y_1 = 2

f(x1,y1)=21.1y1x1=21.120.5=21.1=0.9f(x_1, y_1) = 2 - 1.1 \cdot y_1 \cdot x_1 = 2 - 1.1 \cdot 2 \cdot 0.5 = 2 - 1.1 = 0.9

y2=y1+hf(x1,y1)=2+0.50.9=2+0.45=2.45y_2 = y_1 + h \cdot f(x_1, y_1) = 2 + 0.5 \cdot 0.9 = 2 + 0.45 = 2.45

Step 3: From x=1.0x = 1.0 to x=1.5x = 1.5

x2=1.0,y2=2.45x_2 = 1.0, \quad y_2 = 2.45

f(x2,y2)=21.1y2x2=21.12.451=22.695=0.695f(x_2, y_2) = 2 - 1.1 \cdot y_2 \cdot x_2 = 2 - 1.1 \cdot 2.45 \cdot 1 = 2 - 2.695 = -0.695

y3=y2+hf(x2,y2)=2.45+0.5(0.695)=2.450.3475=2.1025y_3 = y_2 + h \cdot f(x_2, y_2) = 2.45 + 0.5 \cdot (-0.695) = 2.45 - 0.3475 = 2.1025

Step 4: From x=1.5x = 1.5 to x=2.0x = 2.0

x3=1.5,y3=2.1025x_3 = 1.5, \quad y_3 = 2.1025

f(x3,y3)=21.1y3x3=21.12.10251.5=23.473625=1.473625f(x_3, y_3) = 2 - 1.1 \cdot y_3 \cdot x_3 = 2 - 1.1 \cdot 2.1025 \cdot 1.5 = 2 - 3.473625 = -1.473625

y4=y3+hf(x3,y3)=2.1025+0.5(1.473625)=2.10250.7368125=1.3656875y_4 = y_3 + h \cdot f(x_3, y_3) = 2.1025 + 0.5 \cdot (-1.473625) = 2.1025 - 0.7368125 = 1.3656875

Summary of Results

Using Euler's method, the approximate values of y(x)y(x) at each step are:

  • y(0.5)2y(0.5) \approx 2
  • y(1.0)2.45y(1.0) \approx 2.45
  • y(1.5)2.1025y(1.5) \approx 2.1025
  • y(2.0)1.3656875y(2.0) \approx 1.3656875

Conclusion

The approximate solution of the differential equation using Euler's method over the interval x=0x = 0 to x=2x = 2 with a step size h=0.5h = 0.5 has been calculated.

Would you like more details on the calculations, or do you have any questions?

Related Questions

  1. How would the solution change if the step size hh were smaller, say h=0.1h = 0.1?
  2. What is the exact solution to the differential equation, and how does it compare to the Euler's method solution?
  3. How does Euler's method compare to other numerical methods, such as the Runge-Kutta method?
  4. What are the limitations of using Euler's method for solving differential equations?
  5. How does the error in Euler's method change with different step sizes?

Tip

When using numerical methods like Euler's method, smaller step sizes generally lead to more accurate approximations, but they also require more computations.

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Math Problem Analysis

Mathematical Concepts

Differential Equations
Euler's Method

Formulas

Euler's method formula: $y_{n+1} = y_n + h \cdot f(x_n, y_n)$

Theorems

-

Suitable Grade Level

Undergraduate