The period of a sinusoid 

 is 

, so any range such that 

 will give two complete periods.
 
        
        
        
Answer:
11. screenshot attached
12.screenshot attached
13. C
14. B
15. D
16. A
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
Circunferencie can be writen also as a fuction of the diameter of the circle
C = pi*D
Where
D = circunferene diameter
Step-by-step explanation:
C = 2.pi.R = 2.R.pi 
In a circle 2.R = D 
So, 
C = pi.D