The terminal ray of angle β, drawn in standard position, passes through the point (−5, 2√7).
What is the value of cosβ?
Enter your answer, in simplest radical form, in the box.
cosβ
2sqrt (7) = sqrt (28)
r = sqrt [ 5^2 + (sqrt (28))^2 ] = sqrt [ 25 + 28 ] = sqrt (53)
This is an angle in Q2.....the cos is negative here....so.....
cos B = -5 / sqrt (53) = -5sqrt (53) / 53
