How do you find limits on a graphing calculator?

1 Answer
Sep 24, 2014

I am not sure if there is a TI-84 Plus function that directly finds the value of a limit; however, there is a way to approximate it by using a table. Let us approximate the value of the limit

#lim_{x to 1}{sqrt{x+3}-2}/{x-1}#

Step 1: Go to "Y=", then type in the function.

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Step 2: Go to "TBL SET" (2nd+WINDOW), then set TblStart=.97 and #Delta#Tbl=.01.

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(Note: TblStart is the starting x-value in the table, so put a number slightly smaller that the number x approaches. #Delta#Tbl is the increment value in the x-column, so make it sufficiently small for the precision you need.)

Step 3: Go to "" TABLE (2nd+GRAPH).

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As you can see in the table above, the function value (#Y_1#) approaches 0.25 (or 1/4) as x approaches 1; therefore, we conclude that

#lim_{x to 1}{sqrt{x+3}-2}/{x-1}=1/4#