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anonymous

  • one year ago

thanks

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  1. anonymous
    • one year ago
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    You are going to want to use a double angle identity

  2. anonymous
    • one year ago
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    Do you still remember you Double angle formulas?

  3. anonymous
    • one year ago
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    kind of

  4. anonymous
    • one year ago
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    If you don't you can quickly find them on the net with a quick search :)

  5. anonymous
    • one year ago
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    got it then what

  6. anonymous
    • one year ago
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    From there, it is usually trial and error to see what you get in the end, how would you start this one off ?

  7. anonymous
    • one year ago
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    Use a double angle formula for the left side and convert the right side in terms of sin and cos

  8. anonymous
    • one year ago
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    So straight away we can change Sin(2x) into 2SinxCosx

  9. anonymous
    • one year ago
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    2cos(2x)/sin(2x)= 2sinxcosx

  10. anonymous
    • one year ago
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    No just Sin(2x) = 2SinxCosx

  11. anonymous
    • one year ago
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    The Cos(2x) is something we have to play around with, since there are three variants of this particular double angle

  12. anonymous
    • one year ago
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    x=0.15+0.2 dot n

  13. anonymous
    • one year ago
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    Ummm... I not entirely sure how you got that ...

  14. anonymous
    • one year ago
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    In this question we are proving that LHS = RHS not finding a value for x

  15. anonymous
    • one year ago
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    ow got it so what are we doing next

  16. anonymous
    • one year ago
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    Alright, I'll show you what I got, and lets work from there

  17. anonymous
    • one year ago
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    thanks

  18. anonymous
    • one year ago
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    = 2Cos(2x) Sin2(x) = 2[1-sin^2x] 2SinxCosx

  19. anonymous
    • one year ago
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    is that final answer

  20. anonymous
    • one year ago
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    Not even haha, its just the first step ^^

  21. anonymous
    • one year ago
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    lol then what

  22. anonymous
    • one year ago
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    So from there -> Expand inwards 2 - 2Sin^2x 2SinxCox

  23. anonymous
    • one year ago
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    No split the fraction into: 2 - 2Sin^2x 2SinxCosx 2SinxCosx

  24. anonymous
    • one year ago
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    so sin^x

  25. anonymous
    • one year ago
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    Firstly we'll solve this part first: 2 2SinxCosx

  26. anonymous
    • one year ago
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    From here, we can clearly cancel the two's out ^^ So it will become 1 SinxCosx

  27. anonymous
    • one year ago
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    So you say to your self, how do we get tanx? out of 1 SinxCosx well remember that sinx / cosx = tanx

  28. anonymous
    • one year ago
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    Be careful. You can't get tan out of 1/sinxcosx

  29. anonymous
    • one year ago
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    We have to move the Sinx into the numerator, by taking the reciprocal of that. Note that the reciprocal is different from inverse

  30. anonymous
    • one year ago
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    Just like this mate, (Sinx)^-1 Cos (Tanx)^-1 = Tan^-1x -> Apply the inverse of Tan to get Cot Cotx

  31. anonymous
    • one year ago
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    Sorry I meant, the reciprocal of tan to get cot ><

  32. anonymous
    • one year ago
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    its all good thanks

  33. anonymous
    • one year ago
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    Now we have to fine the other part, which is straight forwards stuff :) 2Sin^2x 2SinxCosx

  34. anonymous
    • one year ago
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    So we have to get Tanx out of 2Sin^2x 2SinxCosx

  35. anonymous
    • one year ago
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    How would you approach in doing this?

  36. anonymous
    • one year ago
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    get rid of two 2sin and be left with xcosx?

  37. anonymous
    • one year ago
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    if only XD But your procedure is a bit off >< I'll show you :)

  38. anonymous
    • one year ago
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    lol thanks

  39. anonymous
    • one year ago
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    So we can cancel out the two's to get 2Sin^2x = Sin^2x 2SinxCosx SinxCosx

  40. anonymous
    • one year ago
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    Because the two's are just coefficients in front of the terms, they don't act like terms themselves :)

  41. anonymous
    • one year ago
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    Anyways, from there notice how Sin^2x has a power of 2 That means Sinx . Sinx = Sin^2x

  42. anonymous
    • one year ago
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    So by working out we get Sinx . sinx Sinx Cosx

  43. anonymous
    • one year ago
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    We can easily cancel the Sinx / sinx to get 1

  44. anonymous
    • one year ago
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    And finally <Drums> 1 . Sinx = Tanx Cosx

  45. anonymous
    • one year ago
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    And so we have proven that 2cos(2x)/sin(2x)=cot(x)-tan(x)

  46. anonymous
    • one year ago
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    so its cosx :)

  47. anonymous
    • one year ago
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    Ah just remember that Sinx/cosx = tanx :)

  48. anonymous
    • one year ago
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    thanks so much!!!!!!!!!!!!!!!!!!!!!!!

  49. anonymous
    • one year ago
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    no problem !

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