Tropical the island breeze All of nature wild and free
This is where I long to be
La isla bonita
And when the samba played
The sun would set so high
Ring through my ears and sting my eyes
Your Spanish lullaby

. a function is a relation in which each input has only one output. in the relation , y is a function of x, because for each input x (1, 2, 3, or 0), there is only one output y. x is not a function of y, because the input y = 3 has multiple outputs: x = 1 and x = 2.