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pre calc

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sin 20 pi
cos 9 pi
cos 13pi/2
sin(-17 pi0
are all of these undefined?

  • pre calc -

    sin 20 pi = sin (2 pi*10) = sin 2pi = 0
    cos 9 pi = cos (8 pi +pi). That is 4 times around the circle plus pi so it is really cos (pi) = -1
    No, they are not undefined.

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