SOLUTION: Determine whether each relation is a function. x^2=1+y^2

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Question 90683: Determine whether each relation is a function.
x^2=1+y^2

Answer by vertciel(183) About Me  (Show Source):
You can put this solution on YOUR website!
This relation is not a function.
Proof:
x^2 = 1 + y^2
x = sqrt(1 + y^2)

Substitute y for 1:
x = sqrt(1 + 1^2)
= sqrt(2)

Substitute y for -1:
x = sqrt(1 + (-1)^2)
= sqrt(2)

Therefore, sqrt(2) has two y values: (√2, 1) and (√2, -1)