how to display days in x-axis in chart

Hi

I have to show 4 weeks in such a manner that

1-9(Week1)
10-16(Week2)
17-23(Week3)
24-end of month(week 4)


In x-axis i have to display 9 days of the selected month.

Can you please tell me the logic how to display 9-days


thanks
inam