If cosine theta equals two over three, what are the values of sin θ and tan θ?
cos (theta) = 2 / 3 = x / r
We need to find y = sqrt ( r^2 - x^2) = sqrt ( 3^2 - 2^2) = sqrt ( 9 - 4) = sqrt (5)
sin (theta) = y / r = sqrt (5) / 3
tan ( theta) = y / x = sqrt (5) / 2
