As preparation to use MATLAB, write a MATLAB code to plot a x(t) = cos(2nft) or x(t) = sin(2nft) Let the interval to be 0:0.0001:0.1 for multiple frequencies f = [50 200 500] For each frequency, Plot the following time signals: x1 at f1 = 50 x2 ar f = 200 x3 at f= 500 x4 = x1 + x2 + x3 Include in the report your code and the plot showing title and labeling the axis.