Question
Find the trigonometric function value of angle θ. Cos θ = 2/7 and θ is in quadrant IV. Find sin θ.
Answers
Reiny
cosØ = x/r = 2/7
so x=2 , r = 7
2^2 + y^2 = 7^2
y^2 = 45 = ± 3√5
but we are in IV , so y = -3√5
sinØ = -3√5/7
so x=2 , r = 7
2^2 + y^2 = 7^2
y^2 = 45 = ± 3√5
but we are in IV , so y = -3√5
sinØ = -3√5/7