HP-38G Graphic Calculator
Date: 08/29/98 at 11:36:52 From: Mr.R Subject: Graphic calculator hp38g I just bought an HP-38G. I've tried to graph some math problems, and they just won't graph. Mqybe you know about the HP-38G and can help me. I was trying to graph F(x) = 3x+2 or y = 4x+3.
Date: 10/22/98 at 13:53:46 From: Doctor Andrewg Subject: Re: Graphic calculator hp38g Hi Mr. R! The HP-38G is a pretty amazing calculator, and graphing functions is a good way of understanding them. When you do calculus problems this can be really useful for checking derivatives (slopes), integrals (the area under the curve), and unusual parts of the graph. That's enough advertising for Hewlett Packard - on to your question. If you follow these steps carefully, you will be able to draw these graphs. I assume that you start in the HOME mode. This is where you normally do your calculations. If you are not already there then press the "HOME" button (you may need to press "OK" or "CANCEL" first if you are already doing something else). Now the graphing aplet is a library aplet (it's built in) - so press "LIB" and a screen with a list of six aplets should appear. The order that these appear in depends on which ones you used last (the HP-38G puts those ones at the top to make life easier for you in case you need them again). One of these aplets is the FUNCTION aplet. Move the cursor down to this one (using the arrow keys) and press "ENTER". The screen you are now in is the FUNCTION SYMBOLIC VIEW. If you have defined any functions already then they should appear here next to the F1(X)=, F2(X)=, etc. Go to one of these (any one will do, but F1(X)= should be where your cursor starts) and start typing in your function, say 3X+2. Just press "3", then "X", "+", and "2". You can enter the "X" by using the third function button on the top row of the calculator or by pressing "A...Z" and then "." Now you should have 3X+2 at the bottom of the screen. If you press "ENTER" then it will be copied to the function number you were on and a tick mark will appear next to that function. If any other functions have tick marks next to them then you can remove these by moving to the function and pressing the second function button on the top row. You can graph more than one function at a time if you want by "ticking" more than one function. But we'll start off with just one graph - so untick all the other functions. If you want to see that graph now, you need to press the "PLOT" button. The graph should be on the screen now! Sometimes it takes a few seconds for the HP-38G to plot the graph. To get back to the function screen where you entered the function press "SYMB". Pressing "NUM" will show you values of the function for different values of x. One last hint. When you are in the plot view (after pressing "PLOT") you can press the sixth (rightmost) function button on the top row to bring up a menu. This lets you zoom in on the function and do other neat tricks. If the graphs still don't work for you then "reset" the function aplet by going back to the aplet library (press "LIB") and press "DEL" when you are on the function aplet. The HP-38G will ask you to confirm that you want to reset the aplet - this deletes the functions you have defined and restores all of the options to their defaults. Say yes by pressing the sixth (rightmost) function button on the top row and try the steps I gave above again. Good luck with your calculator - it is a very powerful tool to help you solve maths and statistics problems. Keep experimenting with your calculator - but try to avoid relying on it too much. You never know when your batteries will run out on your calculator - but your brain should be good for a lifetime! - Doctor AndrewG, The Math Forum http://mathforum.org/dr.math/
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