Filter Funciton in Matlab

[Eowe]

Guys I need to get filter function using coefficent of notch filter.First What is transfer function of notch filter?How can I use this transfer function with filter function lets say our input signal

t=0:dt:0.2;
x=cos(2*pi*25*t)+cos(2*pi*50*t);

I want to filter this input signal with filter function

y=filter(b,a,x);

Lastly how can I draw magnitude spectrum of this filter with freqz if notch frequency is 50 hertz?

 

[Tahmid]

https://www.mathworks.com/help/dsp/ref/iirnotch.html

Google returns lots of results: https://www.google.com.bd/?gws_rd=ssl#q=notch+filter+matlab