What does $4sin(arccos(2))-cos(arctan(4))$ equal?

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Answer 1 · 2016-04-25T05:02:16

arc cos 2 is invalid. This is an angle whose cosine is 2. But numerically a cosine cannot exceed 1.

If $a=arc cos 2. cos a = 2 > 1, |cos x| <=1$ . So, arc cos 2 is unreal.

What does 4sin(arccos(2))-cos(arctan(4))4sin(arccos(2))-cos(arctan(4)) equal?