Yefim S. answered • 02/23/21

Math Tutor with Experience

cotθ = y/x if x is opposite leg and y is adjaicent leg: d/dt(y/x) = - csc^{2}θ(dθ/dt) = 1/3

csc^{2}θ = (x^{2} + y^{2})/y^{2} = (5^{2} + 4^{2})/4^{2} = 41/16. So, dθ/dt = - (1/3)·16/41 = - 16/123 s^{-1}