Question 973290
cosine is positive in the first and fourth quadrants, so from the interval, the cosine has to be in the 4th quadrant.  

Cosine 1 (1 radian) is 1 unit less than the 2*pi circumference, which is 6.28.  That would make cos theta=cos 1, be  5.28.  At both 1 and at 5.28, the cosine of theta is cos 1.  The former is excluded by the interval given.