Can't get consistent magnitude response in MATLAB

1. How do you find the magnitude of a response in Matlab?
2. How do you show frequency response in Matlab?
3. Which commands are used to calculate magnitude and phase response?

How do you find the magnitude of a response in Matlab?

You can also click the Magnitude and Phase Response button on the toolbar or select Analysis > Magnitude and Phase Response to display the plot.

How do you show frequency response in Matlab?

w = linspace(0,pi); h = freqz(b,a,w); calculates the complex frequency response at the frequency points in w for the filter defined by vectors b and a . The frequency points can range from 0 to 2π.

Which commands are used to calculate magnitude and phase response?

fs=100; t=0:1/fs:5; x=4*cos(2*pi*10*t+pi/6); X=fft(x); n=length(x); c=(-1*fs)/2:fs/n:fs/2-fs/n; subplot(4, 1, 1),plot(t,x); subplot(4, 1 ,2),plot(c,fftshift(abs(X))); subplot(4, 1, 3),plot(c,phase(X)); subplot(4,1 ,4),plot(c,real(X)); ...... why did use this statement (( n=length(x);))??