11th grade maths
posted by fatima .
A.give an example of a function whose domain is {3,4,7,9}?
and whose range is {1,0,3}
B.Find two different functions whose domain is {3,8}and whose range is {4,1}
C Explain why there does not exist a function whose domain is {1,0,3} and whose range is [3,4,7,9}
D.Give an example of two different functions f and g ,both of which have the set of real numbers as their domain ,such that f(x)=g(x)for every rational number x
E.Give an exampleof a function whose domain equals the set of real numbers and whose range equals the set of integers
please give me th e detailed explanation
show me the work

A: y = 4  x8
B:
y = x7
y = 7  x14
C: one of the domain values must map to 2 range values. Not a function.
D: tricky, if you want f=g only for rational numbers. If f and g are continuous, then f=g for all reals.
E: y = ⌊x⌋ where ⌊x⌋ is the greatest integer less than or equal to x. Equivalent to xmod(x,1) 
How do you fiind the averege rate change