14-3-1

Graphing a Second Order Differential Equation

14-3 Graphing a Second Order Differential Equation

This section explains how to input a second order differential equation and draw a slope field, and how to graph the solution curve(s) for a second order differential equation based on given initial conditions.

With this application, a second order differential equation is input in the form of a set of two first order differential equations.

Drawing the Phase Plane of a Second Order Differential Equation

A phase plane is the family of solutions of either a second order differential equation or two first order differential equations of the form x’ = dx/dt = f(x,y) and y’ = dy/dt = g(x,y). A single second order differential equation can also be graphed, but it must be written as two first order differential equations.

Example: To input {x’ = x, y’ = −y} and draw its phase plane

uClassPad Operation

(1)On the application menu, tap .

This starts up the Differential Equation Graph application and activates the differential equation editor ([DiffEq] tab).

(2)Tap [Type] - [2nd (Phase Plane)] or the B toolbar button.

(3)Use the differential equation editor to input x’ = x, y’ = −y.

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