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Mathematics 17 Online
OpenStudy (anonymous):

I'm really confused on how to do this: Find the indicated limit, if it exists. limit of f of x as x approaches 5 where f of x equals 5 minus x when x is less than 5, 8 when x equals 5, and x plus 3 when x is greater than 5

OpenStudy (solomonzelman):

please write it out, or draw it.

zepdrix (zepdrix):

I think I can get it formatted :) One sec.

zepdrix (zepdrix):

\[\Large\rm f(x)=\cases{5-x,&x < 5\\ \rm 8\qquad~,&x = 5\\ \rm x+3,&x > 5}\]So this is our f(x), yes? Please don't look at my code, it's so sloppy lol

zepdrix (zepdrix):

We don't actually care what the function equals AT x=5. The limit tells us what happens as we get closer and closer, but not actually at the location. So we'll ignore the middle piece.

zepdrix (zepdrix):

When we approach from the left side, \[\Large\rm \lim_{x\to5^-}f(x)=\lim_{x\to5^-}(5-x)\] We use the branch of our piece-wise function that corresponds to where we are.

zepdrix (zepdrix):

Evaluating the limit tells us that the function is approaching 0 from the left side. Understand what I did there? Do you think you can do the right sided limit?

OpenStudy (anonymous):

0 and 8

OpenStudy (anonymous):

@zepdrix

OpenStudy (anonymous):

Is this the piece wise function?

OpenStudy (anonymous):

so it would be dne bc 0 isn't equal to 8 right?

zepdrix (zepdrix):

Yes, very good! :) The limit from the left does not agree with the limit from the right. So the limit of the function, as x approaches 5, does not exist.

OpenStudy (anonymous):

thanks for the help :) and sorry i took long

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