How to add different shaded Color to the back ground of a graph?

a = 0:0.1:2*pi;

b = sin(a);

plot(a,b)

i have written a simple code of sin wave.. i want to add diffrent background colours to different regions or bands.. for example 0-2 some colour, 2-4 some other colour.. as shown in a picture added with this question.

i have tried "area" & "Fill" function but not getting desired results.

Answer 1

[Image Analyst]

Try fill or patch

[taimour sadiq]