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    temporary dumbness.
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    All of these questions are the same

    what is the minumum value that cos X can be?

    so what is the minimum value of 5 cos X

    and therefore minimum value of f(t)
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    I got 10 + 5(cos(15t)-53.1)
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    (Original post by gdunne42)
    All of these questions are the same

    what is the minumum value that cos X can be?

    so what is the minimum value of 5 cos X

    and therefore minimum value of f(t)
    but i get the minimum value as -5.
    so cos(15t) - 53.1 = 180???????????????
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    How'd you do it then?
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    (Original post by Get Cape.Wear Cape.Fly.)
    but i get the minimum value as -5.
    so cos(15t) - 53.1 = 180???????????????
    Assuming your rearrangement is correct

    part c
    10 + (-5) =

    part d
    cos ((15t) - 53.1) = -1
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    The minimum is 5 because it's 10-5 =5 because cos(15t)-53.1)=-1

    for d) it's 15t-53.1 =180 because you inversed it already so you don't need cos there.
    then you find t.
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    ok i got it
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    (Original post by Get Cape.Wear Cape.Fly.)


    These are my previous answers: 3cos(theta) + 4sin(theta) = R(cos(theta) -53.1)

    Maximum value = 5
    The value for which it occurs = 53.1

    :confused:

    How do I do c) and d)?
    For c) minimum when cos(15t-53.1) = -1 ( what is the minimum value in the cosine graph? )

    For d) minimum when 15t- 53.1 = 180 ( again using the cosine graph)
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    (Original post by FZka)
    For c) minimum when cos(15t-53.1) = -1 ( what is the minimum value in the cosine graph? )

    For d) minimum when 15t- 53.1 = 180 ( again using the cosine graph)
    yep i already got it, no worries.
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    (Original post by Get Cape.Wear Cape.Fly.)
    yep i already got it, no worries.
    Okay, good luck.
 
 
 
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Updated: January 17, 2010
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