Quantcast

A community for students. Sign up today!

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

Confusionist

  • 11 months ago

Can someone help me solve this? cos(x^2+45)+tan(4x+90) = sin(3x+120) A step by step would be great.

  • This Question is Closed
  1. xlegendx
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 0

    by solving do you mean proving?

  2. Confusionist
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Yes. :)

  3. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    What methods have been discussed?

  4. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    We are solving for x not proving this. This isn't an identity.

  5. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    Or does it say to disprove or prove?

  6. Confusionist
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Ah yes, my bad. It says solve.

  7. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    Can you tell me what methods in class have been discussed?

  8. Confusionist
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    None, this is from a book with only problems I picked up at barnes and noble. We haven't done this and wont do it for another year or two. I've had no problems with the book up to this point.

  9. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    can you tell me what methods the book has discussed?

  10. Confusionist
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    None. It's a book of only problems. It starts from Geometry and works it's way up in problems.

  11. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    Name of book please

  12. Confusionist
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Math Review for the High School Classroom

  13. Confusionist
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    I looked for it online and can't find it.

  14. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    I didn't see the book. :( So there are no examples?

  15. Confusionist
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    No examples, just questions. :c How did you learn it?

  16. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    Honestly, I don't know without seeing some example or them mentioning some method they want to use.

  17. Confusionist
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Ah, okay. Thanks, anyway. :)

  18. shamil98
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 0

    cos(x^2+45)+tan(4x+90) = sin(3x+120) cos(x^2+45)+sin/cos(4x+90) = sin(3x+120) dividing everything by sin. tan(x^2+45) + sec(4x+90) = 3x + 120 i don't remember trig that well, but you can convert it to this i think.

  19. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    You can't do that... Like you can't divide by the trig part The trig part is a function not a number or variable on its own

  20. shamil98
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 0

    oh

  21. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Are the angles in radians or degrees?

  22. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    I'll assume degrees for now.

  23. Confusionist
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Degrees, yeah. ^^

  24. hartnn
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 0

    45,90,120 suggest they are in degrees... we can convert sin and cos in tan, like cos A = tan (sqrt (1-A^2)/A) something like this and then use tan A+tan B formula...... but if thats possible, the algebra is going to be very ugly....

  25. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    but @hartnn tan(90) does not exist you were talking about the sum identity for tan right?

  26. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @myininaya tan(a+90) = -1/tan(a), since they're perpendicular.

  27. hartnn
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 0

    not tan(A+B) tan A +tan B , where B = 4x+90 and yeah, tan (A+90) = - cot 90 so maybe convert cos into cot and use cotA-cotB formula... i don't think that will be of any use though....

  28. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1388481204906:dw|

  29. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    I don't like the x squared part much.

  30. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Series solution is what I'd prefer to us,e but not without an attempt with standard algera.

  31. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    or maybe the whole problem i don't see how to do it with algebra/trig He said it was for high school though

  32. hartnn
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 0

    even wolf doesn't give integral or rational solutions...

  33. Confusionist
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Yes, I'm a junior in high school, but the book said High School. It extends way past what I expect to learn in High School, though. I think they may have the age range a bit messed up.

  34. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    No simple way to solve at that level.

  35. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    @primeralph if you want, can you show me your series thing you were talking about? You know if you want to.

  36. Confusionist
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    I might just go and ask one of the professors at the college I intern at. Thanks for your help, guys. :)

  37. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    First I'd have to convert all to radians.

  38. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Then find a way to represent the equation as a DE, or simply use the Taylor power series.

  39. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    what is equivalent to a (1 radian) squared? That bugs me. The little square there.

  40. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    What I'm saying is I'm not used to looking at angles being squared

  41. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1388481895287:dw|

  42. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @myininaya Yeah I understand, but you'd have to extend your thinking beyond expecting trig to only apply to angles.

  43. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    It will be extensive, but in the end, there might be real solutions.

  44. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    x^2 and 45 will have different units

  45. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    we have x^2=a^2 (degs)^2 and 45 is just in degs not degs^2

  46. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    The x^2 term will be set to have some correction factor. After taking a look at it, I think it's solvable algebraically. It's just long.

  47. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    And with a lot of restrictions to be imposed.

  48. hartnn
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 0

    those ugly solutions http://www.wolframalpha.com/input/?i=cos%28x%5E2%2B45%29%2Btan%284x%2B90%29+%3D+sin%283x%2B120%29&dataset=

  49. primeralph
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Don't think you used radians. Wolfram is radians by default.

  50. hartnn
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 0

    doesn't make much difference http://www.wolframalpha.com/input/?i=cos%28x%5E2%2Bpi%2F4%29%2Btan%284x%2Bpi%2F2%29+%3D+sin%283x%2B2pi%2F3%29

  51. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    wolfram doesn't want to solve it this is the way input it cos((x deg)^2+45 deg)+tan(4x deg+90 deg)=sin(3x deg+120 deg) http://www.wolframalpha.com/input/?i=cos%28%28x+deg%29%5E2%2B45+deg%29%2Btan%284x+deg%2B90+deg%29%3Dsin%283x+deg%2B120+deg%29

  52. myininaya
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 3

    Maybe it doesn't like the unlike units being added either idk

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

    • Attachments:

Ask your own question

Ask a Question
Find more explanations on OpenStudy

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.