Is the equation of a circle x2+y2=1 is a function ? Justify your answer.
If not then what is the meaning of a circular function?
To see whether a particular expression is a function or not draw the graph
and draw vertical line if it intersects the graph in more than one point it is
not a function
Simply, draw the graph. If for a particular value of x, you have two values of y then it is not a function in x , because as you know that if
f:A->B , then for any element in set A there is one and only one element corresponding to it in set B.
NOTE:-NO closed curve on the 2D graph can represent a function.