Question

How do you find limits on a graphing calculator?

Answer 1

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.

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

(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).

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`