## Ode Solver: Type and Solve an ODE

Pick and drag new initial point in the viewer window. This modifies
the initial `x`

and `y`

values. Initial values of
higher derivative of `y`

can be modified inside the text
field `Initial y`

.

Type a new differential equation. Whenever you type in a text field
press `enter` to submit your changes. Use keyboard key `i`

to switch back to mode allowing picking of initial values:

i | pick initial `x`
and `y` values |

The integrator is a fourth-order Runge-Kutta method with constant step size.

### Controls in Project Panel:

ODE text field | Type a new ordinary differential equation.
Higher derivatives of `y` must be denoted ```
dy, d2y
``` or `d3y` . In this text field you
can use all mathematical functions shown in
Expressions.html. |

Text field "Order" | Defines the order (highest derivative of `y` )
of the differential equation |

Slider "Step Size" | Discretization for `x` -values |

Slider "Length" | Length of the `x` -interval to
evaluate the differential equation. |

Slider "Initial x" | Minimum value for `x` -interval |

Text fields "Initial y" | The first text field shows the initial `y` -value,
the second text field shows the initial value of the first
derivative of `y` , if "Order" is greater than 2,
further text fields for the higher derivatives are
displayed. |

View source code (for details go to JavaView
tutorial):

PaExprOde.java of applet

PjExprOde.java of project

PjExprOde_IP.java of info panel.