A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

I'm confused with this question...

  • This Question is Closed
  1. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

  2. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I keep getting the last 2 parts wrong >.<

  3. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    For #3 shouldn't it just be base times height divided by 2?

  4. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    |dw:1437018844512:dw|

  5. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    Keep in mind, the definite integral gives the "signed" area between x axis and curve

  6. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Right so it's (2x2)/2 isn't it?

  7. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    @ganeshie8 what does that mean?

  8. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    that just means, definite integral gives the "negative" of the area below x axis and "positive" of the area above x axis

  9. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Ohhh right, so in that case isn't it only -2?

  10. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Ahh yep, that was my mistake!!

  11. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    |dw:1437019097211:dw|

  12. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Haha right on!! :D that's correct... now what about the last one?

  13. Astrophysics
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    oOoOoOo

  14. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    Just to be clear : Area is never negative. But the definite integral doesn't give you the actual area, it gives you the "signed" area. A negative sign is added to the area below x axis and a positive sign to the area above x axis

  15. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Ahaha XD lol @Astrophysics

  16. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Mhmm that makes sense!

  17. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    Find the blue area and add up everything |dw:1437019419001:dw|

  18. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    But that shape's neither a rectangle nor a triangle...

  19. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    try again, its not hard for you im sure

  20. Astrophysics
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Easy way, err Hint: |dw:1437019699663:dw|

  21. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1437019750270:dw| or like this?

  22. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    looks good, keep going and finish it off

  23. Astrophysics
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Yeah, exactly :D

  24. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    So that small triangle's area would be 2(-1) / 2 = -1 and then the rectangle above it... 2(-1) = -2 so then would it be -1 - 2 = -3 ?

  25. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I feel like I'm doing it wrong :/

  26. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Yep its wrong

  27. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    Keep in mind : Length, area and volume can never be negative by the very definition

  28. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    |dw:1437020002007:dw|

  29. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Ohhh so no negative sign in the calculations but at the end we just say its negative since its below the x-axis?

  30. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    Yes, the area in its usual interpretation is always positive. To work the definite integral between 0 and 9, simply add up the areas above x axis and subtract the areas below x axis

  31. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    |dw:1437020162395:dw|

  32. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I got 1! and it's CoRrEcT :DDD Thanks so much @ganeshie8 & @Astrophysics!! You guys are the best! :D

  33. Astrophysics
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Lol I didn't do much, it's all ganeshie and his amazing explanations xD

  34. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    @Astrophysics you both did a lot! :D It all helped :D

  35. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Thanks again!

  36. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    np :) in light of above problem, just want to give you this result : If \(f(x)\) is odd function, then \[\int\limits_{-a}^a f(x)\, dx = 0\] try figuring out why that must be true when you're free and if you want to :)

  37. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Yeah my prof was saying something about even and odd functions too... like because even functions are symmetric or something like that...? xD lol

  38. ganeshie8
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    Yes it has to do with symmetry about origin (0, 0). It would be more fun if you figure it out on ur own because you're not very far from seeing it on ur own. Good luck!

  39. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Yuppers! Haha thanks! :D

  40. Astrophysics
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Yeah, that's a fun one, you can try the trig functions and see as well

  41. Astrophysics
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Also for even then \[\int\limits_{-a}^{a} f(x) dx = 2 \int\limits_{0}^{a} f(x) dx\] try working this out to

  42. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Oooh you guy know so much about calculus *_* hahaha thats awesome! Will definitely look at those :D

  43. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    guys* xD haha

  44. Astrophysics
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Lol, well I don't know about ganeshie (he's probably mastered it) but I'm still learning...especially vector calculus that course was weird xD, I still don't fully understand it.

  45. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Oh myyy... if you don't understand it i wonder how terrible that course would go for me XD Lol

  46. Astrophysics
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    No, I think you will be fine, I just had a later start at math, I didn't "really learn" math till I was around 18...and I'm not too far from that right now haha. So I guess I struggle a bit more in understanding the concepts but I guess it's not too bad, I've learnt quite a few things past 2 years :P

  47. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Haha thats pretty awesome!! xD Well, all I know that this is gonna be the last math course I'll be taking for a while XD hahaha

  48. Astrophysics
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Hehe, I used to hate math and say the same thing, now I just want to keep learning it :P

  49. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    LOL it was the exact opposite for me!! I graduated from high school with a Pre-Calculus score of 99% (and i LOVED math) .... I'm not gonna tell you my grades now :P hahaha

  50. Astrophysics
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Haha, well I'm not going to tell you what to do, I think you will figure out doing what you enjoy xD, anyways have fun learning calculus, integrals are pretty awesome, but frustrating at times but that's the fun part! So enjoy!

  51. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Thanks!! :D You're super kind... and smart =D

  52. Astrophysics
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Haha, thanks and right back at ya :D

  53. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Haha merci beaucoup ;D

  54. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.