Answer:
It is not a function.
Step-by-step explanation:
x^2 + y^2 = 4.
Let x = 1:
(1)^2 + y^2 = 4
y^2 = 4 - 1 = 3
So y = √3, -√3.
So we see that for one value of x we get 2 values of y.
So the relation is a one-to-many relation which is not a function.
Functions are either one-to-one or many to-one.
