At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
Its A B C D going down from top to bottom. Sorry i couldnt figure and other way to get the pic's
So Swordsman, same reasoning as with your last question. Pick any value x. If it has two values for y, then it isn't function (because you can't give me a definite answer of what f(x) is at that point). If all values of x have unique y values, then it's a function.
I understand That.. its just i dont understand the way the charts are set up. how do i know what the X values are?
So see the line? Pick any part of the line, a point in it. Find the x and y coordinate of that point. That is the (x,y) coordinate there. You cannot have two points on that line with the same x coordinate. Eg (0, 3) and (0,2). If you can find any two points like that, it isn't a function.
Looking at picture B. See when x = 0? What are the y values there?
2 and -2?
Yep, very good. So would that be a function?
no.. Becuase it cant be the same number value?
Exactly, well done! You can't have two identical x values. Now let's look at the first picture A. Can you see if that's a function or not?
so i can say c is wrong too?
That's right, good work.
so its a or d.. on d its just dots.. so does that mean i can cut out d.. and the answer would be a>?
Nope. For d there are only four unique points as you can see. But for part a, there are an infinite number of points (you can imagine how many dots there are joined together to make that line).
d can still be a function, but to prove it's not, you need to find an example where two x values are the same, can you think of any?
-4 and -2?
-2 only has one unique y value (-5), so that wouldn't proof it isn't a function. But you're right about -4, since that has two y values (both -1 and 5). So you've shown it isn't a function, well done.
oh.. on A its the same - and + number so on A B and C it cant be the function.. so that leaves D as the answer! Right?
D isn't a function. But A is. Because in A, you can pick any value x, and there is only one unique value of y. Try it and see if you can find where that isn't true. You shouldn't find anywhere.
*Face Palm* oh noes.. im so blonde!!! THANKS FOR THE HELP!! :D
No problem =)