Find the missing coordinate of p, using the fact that p lies on the unit circle in the given quadrant.

P( ), -3/7

1 answer

do you mean P( ...., -3/7) ?

x^2 + (-3/7)^2 = 1^2
x^2 = 1 - 9/49 = 40/49
x = ±√40/7 = ± 2√10/7

we see that the y is negative, so the point could be in III or IV, thus the ±