As far as I can tell, that isn't a function at all.
x = 0 produces y = -2 and y = 4, which can't happen.
Please don't use all caps, that's really, really irritating.
Answer:
D
Step-by-step explanation:
cosΘ = 
= 
Answer:
1. Not a function.
2. This is a function.
3. This is a function.
Step-by-step explanation:
1. 13 maps on to 4 and -4 so not a function.
2 and 3 - these both pass the vertical line test so they are functions.
Pick any digit except zero. Write it four times on the same line. If you want to, put a comma between the first and the second one. Shazam ! There's your number !
