Thread: Need LImit help!!!!!!!!!!

find the lim as x approaches positive and negative infinity

(3x^3 - x +1) / (x + 3)

can you explain the answer

Originally Posted by ubhutto

find the lim as x approaches positive and negative infinity

(3x^3 - x +1) / (x + 3)

can you explain the answer

Start by dividing the top and bottom by x, to give



Then as you approach the top goes to and the bottom goes to 1, so the limit is .

Try evaluating the limit as you approach ...

thanks

can you also show me how to get the horizontal asymptote of the graph

Another way to do this to go ahead and divide: . As x goes to either + or - infinity, that last fraction goes to 0 so you only need to consider what happens to determines the limit.

If you know what a "horizontal asymptote" is, you should realize that knowing the limit tells you everything you need to know about the horizontal asymptotes.