math
posted by holly on .
If cos θ = 2/3 and 270° < θ < 360° then determine the exact value of 1/cot

Q4. cosA = 2/3 = X/r,
X^2 + Y^2 = r^2,
2^2 + Y^2 = 3^2,
4 + Y^2 = 9,
Y^2 = 9  4 = 5,
Y = +sqrt5,
Y = sqrt5(Q4).
1/cotA = tanA = Y/X = (sqrt5/2).