MATLAB: How to plot real and imag parts for this signal x(t) = cos(t/4)+cos(3*t/4)

Question

x = cos(t/4)+cos(3*t/4)

for this signal how i plot the real and imag parts

Answer 1

Why do you think there might be any imaginary parts?

Try this:

t = linspace(-2*pi, 2*pi, 1000);
x = cos(t/4)+cos(3*t/4);
plot(t, x, 'b-', 'LineWidth', 2);
grid on;
xlabel('t', 'FontSize', 20);
ylabel('x', 'FontSize', 20);

but if t were complex, you could plot real(x) and imag(x) instead of x.