WAEC - Further Mathematics (2020 - No. 3)
If cos x = -0.7133, find the values of x between 0\(^o\) and 360\(^o\)
44.5\(^o\) , 224.5\(^o\)
123.5\(^o\) , 190.5\(^o\)
135.5\(^o\) , 213.5\(^o\)
135.5\(^o\) , 224.5\(^o\)
คำอธิบาย
cos x = -0.7133
x = cos \(^{-1}\)(0.7133)
= 44.496\(^o\)
x = 180 - 44.495\(^o\)
x = 135.5\(^o\)
and x = 180\(^o\) + 44.495\(^o\)
= 224.5\(^o\)