Statistics and Numerical Methods: Unit V: Numerical Solution of Ordinary Differential Equations

R-k method for simultaneous first order differential equation

Solved Example Problems

Solving the equation dy / dx = f1(x,y,z) and dz/dx = f2(x,y,z) with the initial conditions y (x0) = y0, z (x0) = z0

4.  R-K METHOD FOR SIMULTANEOUS FIRST ORDER DIFFERENTIAL EQUATION

Solving the equation dy / dx = f1(x,y,z) and dz/dx = f2(x,y,z) with the initial conditions y (x0) = y0, z (x0) = z0

[Here, x is independent variable, while y and z are dependent variable]

Now, starting from (x0, y0, z0) the increments, Δy and Δz in y and z respectively are given by formulae.


 

1. Solving the system of differential equations dy/dx xz + 1, dz / dx = -xy for x = 0.3 using fourth order Runge-Kutta method, the initial values are x = 0, y = 0, z = 1.

Solution :

Given : x0 = 0, y0 = 0, z= 1, h = 0.3


 

2. Solve for y (0.1) and z (0.1) from the simultaneous differential equations dy / dx 2y + z; dz / dx = y - 3z; y (0) = 0, z (0) = 0.5 using Runge-Kutta method of the fourth order.

Solution:

Given: x0 = 0, y0 = 0, z0 = 0.5, h = 0.1


 

Statistics and Numerical Methods: Unit V: Numerical Solution of Ordinary Differential Equations : Tag: : Solved Example Problems - R-k method for simultaneous first order differential equation