TRIG,

Can you solve and show me the work in these two equations?
cos(3x)=-1
tan (theta)=-1

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asked by Sarah
  1. Best way to solve it is using a calculator and taking advantage of the arc functions (cos^-1 or tan^-1) to solve it.

    arcCos^-1 (-1)= answer
    arcTan^-1 (-1) = answer

    if you can't use a calculator, then try to remember the unit circle.

    cos(y) = -1 when y = pi or 180 degrees
    So work backwards. cos y = cos 3x = -1

    y=3x

    x= pi/3 or 60 degrees. Since you didn't include bounds in the equation, the solution set is actually (60+120*n) where n is any integer. So x=60, 180, 300, 420... all work.

    Same goes for the tangent. Just work backwards.

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  2. F&arrowbold;

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