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Homework Help: Check another trig behaviour

  1. Aug 30, 2005 #1
    [tex] y=2\cos (\frac {-1} {2}x + 90 ) -3 [/tex]

    I changed the original function to

    [tex] y=2\cos [\frac {-1} {2} (x-180)] -3 [/tex]

    vertical displacement 3 units down
    horizontal translation 180 units left
    Last edited: Aug 30, 2005
  2. jcsd
  3. Aug 30, 2005 #2


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    Science Advisor

    We can't tell- there is no "x" in the original function.
  4. Aug 30, 2005 #3
    aisha: do not confuse radians and degrees.
  5. Aug 30, 2005 #4
    I dont think im confused about radians and degrees some of my trig functions have radians in them so to make things simpler I convert to degrees but in this question i havent done any converting that 90 is in degrees. :smile:
    sorry I added the x in the original function.
  6. Aug 31, 2005 #5
    Did i do this question correctly?
  7. Aug 31, 2005 #6


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    Homework Helper

    Yes, seems correct although I think the horizontal displacement is to the right.
  8. Aug 31, 2005 #7


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    If the original question had 90 in it, then you did it correctly except for the direction of the horizontal translation. If the original question had [itex]\frac{\pi}{2}[/itex] in it, then the value of the horizontal translation is off too.
  9. Aug 31, 2005 #8
    thanks so much the original question does have 90 degrees in it. You are right the horizontal translation should be to the right NOT LEFT! :smile:
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