While they might not have actually the calculus capabilities of the TI-89, the TI-83 Plus and TI-84 Plus have actually two great functions because that dealing with series and sums, the “seq” and also “sum” functions. This tutorial explains how to usage these attributes effectively, and also how to usage the summation feature on more recent calculators.

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### Sequences – The seq function

A **sequence** of number is simply an ordered list of numbers, because that example, 1, 2, 3, 4, 5 or 1, 2, 5, 3, 11, 2, 3. The “ordered” part simply way that each term in the sequence is assigned a details index. In the succession 1, 1/2, 1/3, 1/4, …, the second term is 1/2 and also the fourth term is 1/4. Sequences deserve to be any length, or also be infinite in length.

Sequences are handled on the TI-83 and also TI-84 making use of the seq function. To reach this function from the home screen, press second STAT ▶ 5. On newer calculators, a display will present up i m sorry will overview you with entering the function, despite in any case the syntax is the same.

First, go into the expression girlfriend want, next the variable you’re using, and finally the beginning and finishing values of your variable. The syntax will certainly be pasted onto your screen, for this reason press enter to evaluate. Note that on part older models, you could have to put quotation marks around the equation and also variable name.

A list containing your sequence will be returned.

### Summations – including up Terms

A **summation** is a amount of numbers that space typically identified by a function. Because that example, saying “the sum from 1 come 4 the n²” would median 1²+2²+3²+4² = 1 + 4 + 9 + 16 = 30. Sums can additionally be infinite, detailed that the terms ultimately get close enough to zero–this is crucial topic in calculus. For example, adding up the sum of 1/n does no converge, conversely, the sum of 1/n² converges to π²/6, a quite unexpected result.

There room a pair of methods to advice sums on your calculator. Calculators with more recent operating systems actually have actually a summation function, which can by got to by pressing MATH 0. Through it you have the right to use your arrowhead keys to choose your counting variable (typically X), collection the limits, and enter the expression you desire to evaluate.

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If your calculator doesn’t have this feature, you can perform the same operation by summing increase a sequence: Press second STAT ◀ to with the perform MATH menu, 5 to pick sum, then select the seq function as above. Press get in to evaluate.

Unfortunately, The TI-83 Plus and TI-84 add to don’t have a an approach for analyzing infinity sums, but if you evaluate a convergent summation to sufficient terms (like 100), it have to approximate the boundless sum nice well. Because that example. The sum from X=1 come 100 that 1/x² is 1.635, and the infinite sum is around 1.645.