6. The unit circle with center at the origin is a relation but not a function. a. Find the two functions which are semicircles of the unit circle, and determine
their domains and ranges?
b. Are these functions onto functions? Justify.
c. Find the two functions which are lie in one of the semicircle in part a, and
determine their domains and ranges?
d. Are these functions one to one correspondence functions? Justify.​