linear functions (as in u(t), tri(t), rect(t), etc.)

[ascarpat]

I am trying to solve and hopefully graph functions as in u(t), rect(t), tri(t). I found them in the catalog menu but it does not seem to be working, i get errors when i hit enter.

like 2RECT((t-2)/3)

[Tim_Wessman]

Here's a useful hint, press the HELP button wherever you are in the system (even a cursor positioned in an editline over a command will work) and it will take you to a page for that item. I think you will discover "RECT" is not what you are thinking it is...

Perhaps someone more familar with linear systems will be familar with your terminology, but its been too long for me. 🙂

[Jan_D]

RECT is not a function but a command which can be used in programs.

Like you can find in the User Guide or built- in Help:

Syntax: RECT([G, x1, y1, x2, y2, edgecolor, fillcolor])

Draws a rectangle on G between points x1,y1 and x2,y2 using edgecolor for the perimeter and fillcolor for the inside.

So this means that it draws a rectangle on the screen.

G can be left out, as can edgecolor and fillcolor.

x1 and y1 are the coordinates of the top left corner of the rectangle, and  x2 and y2 the coordinates of the bottom right corner.

The command can be accessed via the menu in the Program Editor.

When you are writing a program you find yourself in the Program Editor and there is a menu button named Cmds.

Press it, next press Drawing, next Cartesian, next Rect.

In order to see something this command has always to be followed by the command Freeze,  accessable via Cmds - Drawing - Freeze.

This is also the reason why you do not see anything when you use the command outside of a program: it is not followed by Freeze, so the image immediately disappears.

There are easier ways to draw a rectangle though, namely in the Geometry app.

When you want to plot linear functions, you can do this in the Function app or Advanced Graphing app, they can also give you intersections.

When you want to get the exact intersections  you have to go to CAS view, so press the CAS key, and use the Solve command.

http://h10032.www1.hp.com/ctg/Manual/c05332710