I am not sure what the argument of the sin is supposed to be. Is that -1*(1/3)= -1/3? That is the only way I can read it, it that what you mean?
Even the meaning of the argument of the cos is not clear. Is that -1 degee? -1 radian?
Generaly the results of trig functions are not expressed in terms of Pi but the arguments are. Radians, the natural unit of angle measure is usually given in terms of Pi, is that what you want?
For ascii text, the traditional names of these functions are:
sin^{-1} = arcsin = asin
cos^{-1} = arccos = acos
Anyways, a quick calculation with my TI-89 hints that there is no way to express the answer as a fraction times π the fraction would have to equal .441506781303..., which is not one I recognize, and does not have a denominator less than 22.
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