Question

Which of the following relations is a function?

a.{(0,2)(1,2)(2,2)(3,2)}
b.{(3,5)(4,7)(5,9)(5,4)}
c.{(2,0)(2,1)(2,2)(2,3)}
d.{(4,5)(6,7)(8,9)(8,11)}

Answer 1

a) vertical line test proves a function. a is the only set of ordered pairs that do not have the same x value. If you have to ordered pairs with the same x value it doesn't pass the vertical line test