Step 1: \ \

if and only if and . \ \

Observe the graph: \ \

\ \	\ \	\ \	\ \	\ \ \ \
	\ \	\ \	\ \	\ \
	\ \	\ \	\ \	\ \ \ \
\ \	\ \	\ \	\ \	\ does not exist \ \ \
	\ is undefined \	\ \	\ \	\ \ \ \

is undefined since there is no solid circle. \ \

is does not exist because .

Solution: \ \

\ \	\ \	\ \	\ \	\ \
	\ \	\ \	\ \	\ \
	\ \	\ \	\ \	\ \
	\ \	\ \	\ \	\ does not exist \
	\ does not exist \	\ \	\ \	\ \ \ \

\ \