The following system has input x[n] = 9 + 2cos(n/2) + 3cos(n) and output y[n]: 5y[n] + 3y[n − 1] + y[n − 2] = 7x[n] + 6x[n − 1] − x[n − 2] . Calculate: (a) the frequency response H(e j ), and (b) the output y[n].

Express the following as a function of a single angle, cos(60) cos(-20) - sin(60) sin(-20)

Do some research and find a city that has experienced population growth. determine its population on january 1st of a certain year. write an exponential function to represent the city’s population, y, based on the number of years that pass, x after a period of exponential growth. describe the variables and numbers that you used in your equation.

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class