Displacement (mm) Time (3 This behaviour can be reduced to an expression for the displacement as a function of time y (t) = e cos ( 2nft) where k = 0.5s and f = 2 Hz a. Calculate the values of f in the interval t - 0 s to t = 1 s for which the value of y() is zero. Hint: consider values at which a cosine function is zero and consider if there are any values at which the exponential function can be zero D. Differentiate f (t) = er#t and g(t) = cos(2n ft) with respect to c. Differentiate the function y(t) to show that the expression for the velocity of the tip as a function of time can be written as: u (t) - -elf [keos(2uft) + 2wf sin(2