Compute Laplace transform using the symbolic toolbox of MATLAB. If you want to compute the Laplace transform of a function, use the symbolic variables. For example, compute the Laplace transform of cos(3t + 45). The variable for the Laplace transform is denoted as Y. Calculate the Laplace transform of cos(3t + 45). Plot the graph with appropriate labels for the x-axis, y-axis, legend, and title.