## math456 3 years ago Need help: A patient receives a 150-mg injection of a drug every 4 hrs. The graph shows the amnt f(t) of he drug in the blood steam after t hours. Find lim of f(t) as t approches to 12(left) and 12(right)m and explain the significance of these one-sided limits.

1. math456

|dw:1347471338357:dw|

2. math456

@phi @Hero ??

3. math456

is it 150 from the left & the right?

4. nj1202

5. math456

okay and what about the significance?

6. nj1202

The significance is that the two-sided limit, or the limit as x approaches 12 exists.

7. math456

but its one sided limit!

8. nj1202

Is this the complete graph?

9. math456

|dw:1347471676369:dw| this is the complete graph

10. nj1202

oh well that's much different then! The limit from the left is 150. The limit from the right is 300. The significance is that the limits from the left show the medicine in the blood left and the limit from the right shows how much medicine the patient has in the blood after another dose.

11. math456

how is it 300 from the right?

12. nj1202

Well, I'm assuming that the open circle is supposed to be directly above the shaded circle at x=12?

13. math456

oh so u mean this: |dw:1347471976602:dw|

14. nj1202

Exactly. If it's directly above, then you follow the graph from either side. You've got it!

15. math456

alright i got it. Thanks for ur help..

16. nj1202

not a problem!

17. phi

The significance of these one-sided limits is that they indicate a discontinuous change in the amount of drug, caused by the injection.