Detailed instructions for use are in the User's Guide.
[. . . ] These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference with radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, you can try to correct the interference by one or more of the following measures:
Reorient or relocate the receiving antenna. [. . . ] In most cases, the variable i is used only while the program is running. :Local i :For i, 0, 5, 1 : Disp i :EndFor :Disp i
If you declare variable i as local, it is deleted automatically when the program stops so that it does not use up memory. An Undefined variable error message displays when you evaluate a user-defined function or run a user-defined program that references a local variable that is not initialized (assigned a value). Line breaks are shown here, but you would type the text in the entry line as one continuous line, such as: Define fact(n)=Func:Local?where the ellipsis indicates the entry line text continues off-screen. In the example above, the local variable m exists independently of any variable m that exists outside of the function. You Must Initialize Local Variables
All local variables must be assigned an initial value before they are referenced. N: EndWhile: Return m: EndFunc
1 is stored as the initial value for m. The TI-89 / TI-92 Plus cannot use a local variable to perform symbolic calculations. DOC TI-89/TI-92 Plus: Programming (English) Susan Gullord Revised: 02/23/01 1:14 PM Printed: 02/23/01 2:18 PM Page 290 of 40
To Perform Symbolic Calculations
If you want a function or program to perform symbolic calculations, you must use a global variable instead of a local. However, you must be certain that the global variable does not already exist outside of the program. Entering a Test Operator
Type the operator directly from the keyboard. Relational Tests
Relational operators let you define a conditional test that compares two values. The values can be numbers, expressions, lists, or matrices (but they must match in type and dimension). Operator True if: Example a>8 a<0 a+b?100 a+6b+1 list1=list2 mat1?mat2
Tip: From the keyboard, you can type: >= for ? = ?
Greater than Less than Greater than or equal to Less than or equal to Equal Not equal to
Boolean Tests
Boolean operators let you combine the results of two separate tests. Operator and or xor True if: Example a>0 and a10 a0 or b+c>10 a+6<b+1 xor c<d
Both tests are true At least one test is true One test is true and the other is false
The Not Function
The not function changes the result of a test from true to false and vice versa. For example:
not x>2 is
true if x2 false if x>2
Note: If you use not from the Home screen, it is shown as ~ in the history area. EndIf structure uses a conditional test to decide whether or not to execute one or more commands. Lbl (label) and Goto commands can also be used to branch (or jump) from one place to another in a program. :If | Then :EndIf
The cursor is positioned so that you can enter a conditional test. If Command
Tip: Use indentation to make your programs easier to read and understand. [. . . ] DOC TI-89: Index (US English) Susan Gullord Revised: 02/26/01 3:52 PM Printed: 02/26/01 3:55 PM Page 600 of 16
P (continued)
point change, PtChg, 307, 482 off, PtOff, 307, 483 on, PtOn, 307, 483 test, ptTest( ), 307, 483 text, PtText, 307, 483 polar coordinate, R4Pq( ), 487 coordinate, R4Pr( ), 487 graphing, 133 ?138 vector display, 4Polar, 480 polyEval( ), evaluate polynomial, 480 polynomials, 9, 72, 76 activity, 402 evaluate, polyEval( ), 480 random, randPoly( ), 488 PopUp, popup menu, 301, 481 power of ten, 10^( ), 537 power, ^, 534, 569 PowerReg, power regression, 262, 481, 571 pretty print, 6, 11, 23, 29 Pretty Print mode, 29, 41, 552 previews. See examples, previews, activities Prgm, execute program, 276, 287, 481 prime number test, isPrime( ), 459 prime numbers, 8 prime, ', 536 problems (new), NewProb, 43, 472 problems in operation. See errors and troubleshooting product code, upgrading, 373, 374 product ID, 55 product( ), product, 482 product, ?( ), 75, 533 programs and programming, 275 ? [. . . ]