Activate a program by clicking on its name in the list.

An "Instructions" window will appear, with information on what the program does and how to use it. To remove the window, click the

Each program displays several buttons. Clicking on one of them (for instance,

After setting the values you want in a window, click the window's

After you have entered the data to set up the problem, clicking on the button labelled

All the programs are set up with resonable sample inputs. The first time you run a program you may want simply to call up the entry window or windows and click "Enter" without making any changes, just to see what the program does.

The 3D graphics in the multivariable calculus applets can be rotated by dragging the mouse over the graphics. Click on the

Each program involves one or more of the variables t, x, y, and z. In the programs concerned with second-order differential equations, the variable z is used also to stand for y', the derivative of y.

The functions are defined by expressions made up from numerical constants and the variables allowed in a particular program combined using the operations and functions listed below.

Operations/Functions |
Meaning |

+, -, *, / |
add,subtract,multiply,divide |

^ |
exponentiation ( a^b is a^{b}) |

abs(x ) |
absoluate value of x |

sqrt(x ) |
square root of x |

ln(x) |
natural logarithm of x |

exp(x) |
e^{x} |

sin(x), cos(x),tan(x) |
sine, cosine, tangent of x (x in radians) |

asin(x),acos(x),atan(x) |
arcsine, arccosine, arctangent of x (x in radians) |

H(x) |
Heaviside function of x, defined by H(x) = 0 for x< 0 H(x) = 1 for x>=0 |

Terms may be grouped using parentheses, and the usual order of operations is followed, with multiplications and divisions done before additions and subtractions.

The * (asterisk) for multiplication may be omitted in products of a number and a variable, and in products of expressions that are both in parentheses.

If the program can't interpret an expression you have typed, it brings up a window to tell you so and invites you to try again. Some possible reasons for rejecting an expression are:

- parentheses not properly matched up.
- use of a variable not allowed for a particular program.
- typing errors such as a comma for a decimal point, which may be hard to distinguish on the screen.