VIEWS: 2,058 PAGES: 3 CATEGORY: Guides POSTED ON: 1/10/2009
A Quick Guide to TI-83 & TI-84 The most important command to learn is 2nd QUIT (press ). If you ever get stuck in a menu or want to exit something (like graphing), then 2 nd quit. FIRST THINGS FIRST ID NUMBER: Your calculator has a unique ID number. This would be helpful to jot down in case of a mix up (of course, your name in sharpie on both parts of the calculator and an identifying sticker could help, too). To find it, press . The id number should be shown. Jot it down _______________________. (of course, to get out of this screen, press 2 nd quit!) CONTRAST: To make your screen lighter or darker, use (the cursor keys) or . You must press 2 nd each time (i.e., you can’t just press 2 nd up, up, up, up, up). Note the number in the top right immediately after you press up or down-it goes from 1 to 9. If you’re at a nine, you need new batteries! MODE: Press to access the settings for your calculator. Unless told otherwise, your modes should look like this: To change a setting, use the cursor keys to move to the new setting, and press . How do we get out of this screen? 2 nd quit! ENTERING EXPRESSIONS The nice thing about graphing calculators is that you (usually) can enter an expression the same way you read it You just need to be careful of a few quirks: NEGATIVES AND SUBTRACTION The calculator uses the subtraction sign for subtraction ONLY. To enter in a negative number, you need to use . For example: Example Keystrokes Answer 3–6 -3 3 – -6 9 If you enter a subtraction instead of negative (or negative instead of subtraction) you’ll get this Usually it’s easiest to press and retype your problem, however, if you want to edit the original, choose 2:Goto by either or . This will put the cursor over the error, which you can then change (we’ll get to editing in the next section). NEGATIVES AND SQUARING As we know –32 means to square the 3, then make it negative, so the answer is –9. The calculator knows that, too. So why is that a problem? Suppose you have to evaluate x 2 when x = -3, which we know is equal to 9. If you type in , you will get –9 as your answer! Two ways to handle this: A) Put parenthesis around negative values when your problem involves powers B) Know that the sign of a number doesn’t matter when you are squaring (or any other even power), so leave the negative off. (of course, if the question asks for –32, put the negative in!) Example Keystrokes Answer 2 x when x = -3 9 OR -x2 when x = -3 -9 OR POWERS To raise to a power higher than 2, use the (above , not the up arrow). Example Keystrokes Answer 34 81 (-3)4 81 OR (-3)3 -27 FRACTIONS The TI-83/84 does not have a fraction button like you may be used to. To enter a fraction, use division. When you are just multiplying, adding, or subtracting, you don’t need to worry about parentheses. However, when raising to a power or dividing, put your fraction in parentheses! Also, when you see a large fraction bar with operations in denominator & numerator, think parentheses! To change a decimal answer into a fraction, use Example Keystrokes Answer 2 4 1.46666667 3 5 22/15 2 4 .533333333 3 5 8/15 2 4 .833333333 3 5 (note: try it without parentheses: do they matter?) 5/6 2 4 Note: we know mixed numbers just mean 5 + 2/3, so we’ll enter: 5 2 15.8666667 3 5 238/15 2 4 Note: you only make the numerator negative! NOT –4/-5! -.5333333 3 5 3 2 1.25 5 1 5/4 SQUARE ROOTS The calculator automatically gives you an open parenthesis when you press the square root button. Make sure you close it where the square root ends in your problem (This is a VERY common error!) Example Keystrokes Answer 16 4 16 5 9 16 5 4.582575695 PI Pi is . Example Keystrokes Answer 2 (note: you do not need the times sign) 6.283185307 2nd ANSWER SHORTCUT Sometimes when working a long problem, you need to know the answers “in between”. To use this answer in the next step, you can either enter in the next operation or use (“2nd answer”). Example Keystrokes Answer 2 3x + 4 = 23 19 3x2 = 19 6.333333333 Note that when I just press enter this, the calculator reads “Ans/3” meaning, it is using the last answer (19) x2 = 6.3333333 I need this answer after my square root sign, so I need to use 2 nd answer: 2.516611478 x=2.516611478 2.516611478 Let’s try to put this in a fraction It gives me the same decimal, meaning that this must be an irrational number! EDITING As you are entering a problem (or after), you may notice a mistake! If you have already entered the problem, will bring it up again for you to work on (you can keep pressing and it will scroll through the last few problems you have entered.) You can then use the arrow keys to move the cursor to the mistake. Then you can use these ways to fix it: Delete: For example, you typed 100 instead of 10. You can delete the second 0. Type over: Suppose you type 45 – 16 instead of 47 – 16. You can move the cursor to the 5 and type the 7. This is also handy when you are given: 17 + 42. Type it once using +, then , and change the + to -. Insert: Move the cursor to where you want insert in front of. Then use and type the missing part. For example, You typed 32+15 instead of 324+15. Move the cursor to the +. Then Forget this!!: gives you a nice blank home screen. And when you’re done with everything, turns it off. Practice with these problems. The answers are shown to quickly check. 65 – 42(7) -47 1 6.441666667 (or we know it as 6.441 6 , it just rounds 6 .4 24 the last decimal) 7 12.284 10.36 - 3.674 4 2.3 (3.1 + 4.98) 18.584 24 + 3(6 – 4.5) 28.5 6.2 4.8 3.2 2 -19.52 789 .140671801…as fraction: 263/193 123 456 (6.2 + 5)3 1404.928 7.5 2 176.7145868 15 4 3 9 4.408881731 2 3 29/35 (as fraction) 5 7 x2 – x – 4 when x = 5 and when x = -7 x = 5, answer is 16 x = -7, answer is 52.