Question 631631
Find all real numbers in the interval [0,2pi] that satisfy the equation. Round to the nearest hundredth.
cos x = -0.23
arccos(-0.23)=1.803( in quadrant II where cos<0)
reference angle=&#960;-1.803=1.339 
2nd angle=1.339+&#960;=4.481 (in quadrant III where cos is also<0)
all real numbers in the interval [0,2pi]: 1.803 and 4.481 radians