Sine Curve plotting using MATLAB codes

Here, time is predefined for a slot and sine function is used. Frequency 'f' is taken 50 Hz.
The code is given below:

t=[0;0.1:20] ;
f=10 ;
x=2*pi*f*t ;
a=sin(x) ;
plot(t,a)
grid on
shading interp ;
colorbar;