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Homework Help: Vector and magnitude

  1. Oct 6, 2008 #1
    1.I only need to know how to get magnitude out of a vector

    2. Suchs as 25m = a cos (60 degrees)

    3. I tried 25m/cos/60degrees but it don't seem right

    please assist I know it isn't a real problem it's just the step that I need help. If you could write it in fomula form AX=A cos (theta) solving for "A". And if you can show me how to solve for "theta" as well please.
  2. jcsd
  3. Oct 6, 2008 #2
    magnitude is simply the length of the vector. if you are using cos then it sounds like what you really need is the x or y component.
  4. Oct 6, 2008 #3
    I see that I may have been unclear Ax is the x component. I have Ax and I hav ethe angle theta what I do no thave is the magnitude.
  5. Oct 6, 2008 #4
    Ax is written A(sub)x(/sub) except that you use brackets.
  6. Oct 6, 2008 #5
    what do you mean solve for A??? thats trivial. A*cos(theta) is no different from A*B.

    theta is a little harder. give me a minute.
  7. Oct 6, 2008 #6
    I have Ax = A cos [tex]\Theta[/tex]
    where I know Ax and [tex]\Theta[/tex]
    how do I find A
  8. Oct 6, 2008 #7
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