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

bmelyk Group Title

i know this is easy but, i just forget how to do it.

  • one year ago
  • one year ago

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

    \[\cos(\arcsin(\frac{ \sqrt{3} }{ 2 }))\]

    • one year ago
  2. ChmE Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    \[\sin^{-1}\frac{ \sqrt{3} }{ 2 }\]This is an angle measurement. Like if you had \[\sin \theta = \frac{ \sqrt{3} }{ 2 }\]You would find theta by taking the inverse. Use your knowledge of the unit circle to find the value of the y coordinate (sine) at sqrt(3)/2. Then once you have this, you can find cos of whatever it was

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

    okay so arc sin is actually sin^-1

    • one year ago
  4. ChmE Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Ya they are used interchangeably.

    • one year ago
  5. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    so it's sin of 30 degrees?

    • one year ago
  6. myininaya Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    \[\text{ Let } u=\arcsin(\frac{\sqrt{3}}{2})\] => \[ \sin(u)=\frac{\sqrt{3}}{2}\] sin( )=opp/hyp So we can do this: |dw:1352310919231:dw| Use Pythagorean thm to find the adjacent side to u. Then you can find cos(u) which is the same as what your question is asking since we \[\text{ let } u=\arcsin(\frac{\sqrt{3}}{2})\] \[\cos(u)=\cos(\arcsin(\frac{\sqrt{3}}{2}))=\frac{\text{ adjacent side to u}}{hyp}\]

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

    right so it's just root 3 over 2

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

    Nope sin(u) is that what is cos(u)?

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

    or it's at 60 degrees and 120

    • one year ago
  10. ChmE Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Based on the unit circle, sqrt(3)/2 (the y value) is at 60 deg. So it would be cos 60deg

    • one year ago
  11. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    60 and 120, right?

    • one year ago
  12. ChmE Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    right it is also at 120. good catch

    • one year ago
  13. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    so i write it as cos(60) ??

    • one year ago
  14. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    so my answer should be 1/2 and -1/2?

    • one year ago
  15. myininaya Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    but arcsin( ) only has range between -90 and 90.

    • one year ago
  16. ChmE Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Thats what I got !!

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

    So you will only have one answer.

    • one year ago
  18. ChmE Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Explain that plx @myininaya . I don't remember that.

    • one year ago
  19. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    i thought that had to be specified

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

    http://en.wikipedia.org/wiki/Inverse_trigonometric_functions He's right. The only answer would be 1/2

    • one year ago
  21. myininaya Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    In order to make sin( ) one to one, we must restrict the domain of sin( ) in order to do this. We chose the restriction [-90 degrees, 90 degrees] So now that are inverse for sin( ) exists, we call it arcsin( ). And arcsin( ) only has range [-90 degrees, 90 degrees]

    • one year ago
  22. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    i can only do this type of problem if it's one to one?

    • one year ago
  23. myininaya Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    I'm a her.

    • one year ago
  24. ChmE Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Sry I meant nothing by it

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

    so if i wanted to do sec(arctan(2)) i do the same thing?

    • one year ago
  26. myininaya Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    I like making a pretty right triangle. :)

    • one year ago
  27. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    huh?

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

    \[\text{ Letting } u=\arctan(2) \] => tan(u)=2 tan(u)=2/1 tan(u)=opp/adj We let opp side of u be 2 We let adj side of u be 1 Let the labeling begin.|dw:1352311632755:dw| Now find the hyp by using the Pythagorean thm.

    • one year ago
  29. myininaya Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    After that, find sec(u) and you are done.

    • one year ago
  30. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    there is no hypotnus tho :s

    • one year ago
  31. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    oh i gott find it lol

    • one year ago
  32. myininaya Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    Yes there is. You find it by using the Pythagorean thm.

    • one year ago
  33. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    square root of 5 is the hyp.

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

    ???

    • one year ago
  35. myininaya Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    Yes:)

    • one year ago
  36. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    okay so now i take sec(squareroot 5)

    • one year ago
  37. myininaya Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    so what is sec(u)

    • one year ago
  38. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    and do i restrict my tan?

    • one year ago
  39. myininaya Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    |dw:1352311961504:dw|

    • one year ago
  40. myininaya Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    sec(u)=hyp/adj

    • one year ago
  41. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    so its just root 5

    • one year ago
  42. myininaya Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    Yep. :)

    • one year ago
  43. ChmE Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Study her method because it was way easier than my explanation.

    • one year ago
  44. bmelyk Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    and i state my domain and range for just sec right?

    • one year ago
  45. myininaya Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    No it was just looking for sec(arctan(2)) which is just \[\sqrt{5}\]

    • one year 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.