Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

DHASHNI Group Title

why integral of( sin x )=-(cos x) ? and how?

  • 2 years ago
  • 2 years ago

  • This Question is Closed
  1. waterineyes Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    What is the derivative of cosx??

    • 2 years ago
  2. DHASHNI Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    - sin x

    • 2 years ago
  3. waterineyes Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Or you can say that the derivative of -cosx is sinx... Now integral is just reverse of derivative.. So whose sinx is derivative of which quantity???

    • 2 years ago
  4. waterineyes Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1342100312222:dw|

    • 2 years ago
  5. waterineyes Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Or you can use Euler's Identities to prove it...

    • 2 years ago
  6. waterineyes Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    \[\large \sin \theta = \frac{e^{i \theta} - e^{-i \theta}}{2i}\] \[\large \cos \theta = \frac{e^{i \theta} + e^{-i \theta}}{2}\] Find the integral of sin theta you will get -cos theta..

    • 2 years ago
  7. estudier Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Other possibilities are to integrate the Taylor Series for Sin x on some interval or from first principles as here http://www.math.com/tables/derivatives/more/trig.htm

    • 2 years ago
  8. lgbasallote Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    a good thing to remember is the integral of a cofunction is alsways negative that explains the negative sign

    • 2 years ago
  9. across Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    lmao she has no clue how to integrate \(\sin\) and there's people suggesting she use Euler's identity, hahaha.

    • 2 years ago
  10. DHASHNI Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    thanks to every one i got the ans!!!!!!

    • 2 years ago
  11. waterineyes Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    She has clue how to integrate but she is asking why?? and mind your language @across

    • 2 years ago
  12. across Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    @DHASHNI, this follows from the differentiation of the trigonometric functions:\[\sin x\implies\cos x\\\cos x\implies-\sin x\\-\sin x\implies-\cos x\\-\cos x\implies\sin x\\\]

    • 2 years ago
  13. waterineyes Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    @across prove them...

    • 2 years ago
  14. across Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    I can Google you a proof in less than five seconds. I don't have to prove anything to you.

    • 2 years ago
  15. waterineyes Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    That is what she is asking... Google??? What else you can do...

    • 2 years ago
  16. DHASHNI Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    @across : i knw the formulas ....... i jus wanna know how integral sinx is (-cos x)........the proof for that~

    • 2 years ago
  17. lgbasallote Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    here's another fun proof \[\int sinx dx\] let u = cosx du = -sin x dx -du = sinxdx \[\implies\int -du\] \[\implies -\int du\] \[\implies -u\] \[\implies -\sin x\]

    • 2 years ago
  18. waterineyes Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Now did you get what she said @across .. If you don't know how to prove them then do not make fun of anybody...

    • 2 years ago
  19. across Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    OH, she wants the PROOF. For all we know, the title may have suggested a geometric interpretation.

    • 2 years ago
  20. waterineyes Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    I think a word known as WHY is sufficient for all the things...

    • 2 years ago
  21. DHASHNI Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    LOL

    • 2 years ago
    • Attachments:

See more questions >>>

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.