Make up a table with columns headed by values of kx running from x = -/2 to

Make up a table with columns headed by values of kx running from x = -λ/2 to x = +λ in intervals of x of λ/4 - of course, k = 2π/λ. In each column place the corresponding values of cos (kx - π/4) and beneath that the values of cos (kx + 3π/4). Next plot the functions 15 cos (kx - π/4) and 25 cos (kx + 3π/4).