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i need a ti-83 plus program that will take the sum of a group of number for me for example: find the sum of the numbers 81-109 inclusive.

By Scorp (Scorp) on Tuesday, October 05, 2004 - 02:31 pm: Edit

nevermind.

By Piman3141 (Piman3141) on Tuesday, October 05, 2004 - 02:41 pm: Edit

0->N
prompt A (this will be first number-81)
prompt B (this will be second number-109)
For (X, A, B
X+N->N
End
Disp N


(-> is the store command, the button above the on/off button)

By Piman3141 (Piman3141) on Tuesday, October 05, 2004 - 02:43 pm: Edit

btw, scorp, why do you use the paragraph separator for one line comments?

It's easier to use //.

You probably already knew this, but anyway, there it is.

By Zenith (Zenith) on Tuesday, October 05, 2004 - 03:06 pm: Edit

The formula is n(a+z)/2 where n is the number of items you have to sum, a is the first and z is the last! So much easier to remember this!

By Piman3141 (Piman3141) on Tuesday, October 05, 2004 - 03:21 pm: Edit

easier to copy a program posted on a website than to remember a formula. Anyway, i was surprised that amitabh hadnt ever heard of this formula, as it is practically a given for any precalc course.

By Hsm (Hsm) on Tuesday, October 05, 2004 - 04:35 pm: Edit

Hey zenith thanx for the formula!

By Vtran31 (Vtran31) on Wednesday, October 06, 2004 - 01:26 am: Edit

thank you! I was trying to derive it myself!

By Whtx (Whtx) on Thursday, October 07, 2004 - 05:49 pm: Edit

0->N
prompt A (this will be first number-81)
prompt B (this will be second number-109)
For (X, A, B
X+N->N
End
Disp N
----------------------------------------------

Can you go over the keys again? Can you type them out line by line as it would appear on the calc? I tried to do the above but it didnt work. How come i could only do the promt key ones? Can you indicate where the line breaks are?

Thanks

By Piman3141 (Piman3141) on Thursday, October 07, 2004 - 08:34 pm: Edit

wha? just put in exactly what's written above (except for the two comments of course). for the "For" statement, while programming, press prgm, then "4". For the "End" statement, press prgm, then "7" i think. The rest is obvious.

btw, a simpler program appears below.

Prompt A,B
(B-A+1)(A+B)/2->C
Disp C


hope this helps