anonymous 5 years ago How do you know if integrals are improper?

1. anonymous

if the function that you're integrating goes to infinity ^_^ I guess

2. anonymous

Okay! Do you know how to tell if they converge or diverge?

3. anonymous

if the answer = a finite number, then it converges, but if your answer = infinity , then it diverges ^_^

4. anonymous

no, it has infinity as one of the limits

5. anonymous

it doesnt "go to infinity" :\

6. anonymous

but this one also works, my professor said that, or maybe I was day dreaming again ._.

7. anonymous

or it could result in division by zero

8. anonymous

Basically, if there is an interval that you are integrating within, ie there are numbers on the top and bottom of the intendant, or the s looking thing, then it is proper. If there are no numbers, and it goes tninfinity, it's improper. You tell if it converges or diverges by seeing if any values cause the function to be indeterminate.

9. anonymous

that's what I meant elec, division by zero = infinity

10. anonymous

$\int\limits_{-\infty}^{\infty } f(x) dx$ something like that

11. anonymous

Does that mean it's improper?

12. anonymous

or $\int\limits_{0}^{1} \frac{e^x}{x}$

13. anonymous

It's improper if there are no limits. The infinity is implied, so it's usually not written.

14. anonymous

there are two cases either the interval of integration is infinite or the function to be integrate becomes infinite at the given interval of integration

15. anonymous

so both of u guys elecengineer and sstrica r right

16. anonymous

lol uzma :)

17. anonymous

:)

18. anonymous

Thanks guys!

19. anonymous

yeh now I get what you me, but I dont like when people say that you get infinity when you divide by zero. Its not 100% mathematically correct, get your definitions in order :P

20. anonymous

np ^_^

21. anonymous

nothing is 100% , there's only 98% elec ^_^

22. anonymous

?

23. anonymous

100% = perfection perfection doesn't exist, but it's good to seek it ^_^

24. anonymous

Wait .. so how do you know if it's converging or diverging again? Converging ends in an actual number and diverging goes to infinity or divides by zero?

25. anonymous

finite number = converge, infinite number = diverge

26. anonymous

It diverges if it has an asymptote.

27. anonymous

torch aren't you supposed to be in bed by now? Lol

28. anonymous

horizontal or vertical?

29. anonymous

Thats how you find if it goes to zero or infinity

30. anonymous

By using the asymptote?

31. anonymous

Either asymptote will cause a divergence. It doesn't matter if it is horizontal or vertical. And I'm going star! Lol gimme a medal and fan me, catch ya later! Lol

32. anonymous

What's a medal?

33. anonymous

Next to my name there's a button. You push it for the person that helped the most or a lot. Haha

34. anonymous

oh okayy

35. anonymous