# Could you check the graph for an equation?

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• Mar 28th 2014, 11:51 AM
canyouhelp
Could you check the graph for an equation?
Am I right about the first equation matching the graph of this? Attachment 30545 If not which one does it match?
• Mar 29th 2014, 06:49 PM
HallsofIvy
Re: Could you check the graph for an equation?
It would help if you would tell us why you think that is the correct response.
But it is easy to see the first one is NOT correct by looking at the point (-1, -1). In fact, you can eliminate all except the one correct response by looking at (-1, -1)!
• Mar 30th 2014, 06:25 AM
canyouhelp
Re: Could you check the graph for an equation?
Quote:

Originally Posted by HallsofIvy
It would help if you would tell us why you think that is the correct response.
But it is easy to see the first one is NOT correct by looking at the point (-1, -1). In fact, you can eliminate all except the one correct response by looking at (-1, -1)!

Well first I tried testing (-1,1) for each equation, but somehow I got that several of them worked :/ So then I tried it on my calculator and I thought the first one looked similar to the graph :/ Maybe I put it in wrong.
• Mar 31st 2014, 05:35 AM
hollywood
Re: Could you check the graph for an equation?
Are the first and second options actually the same equation?

- Hollywood
• Mar 31st 2014, 06:04 AM
canyouhelp
Re: Could you check the graph for an equation?
Quote:

Originally Posted by hollywood
Are the first and second options actually the same equation?

- Hollywood

Oh my gosh. I didn't even notice that. When I tested them I made the second one y'=1/(x^2*y^2). Hmm :/
• Apr 1st 2014, 08:17 AM
hollywood
Re: Could you check the graph for an equation?
So do you see HallsofIvy's solution now? According to the graph, y'(-1,-1) is positive.

- Hollywood
• Apr 1st 2014, 11:22 AM
canyouhelp
Re: Could you check the graph for an equation?
Quote:

Originally Posted by hollywood
So do you see HallsofIvy's solution now? According to the graph, y'(-1,-1) is positive.

- Hollywood

The third one looks like it would work then 1/((-1)*(-1))=1 But if the second one is supposed to by 1/(x^2*y^2) wouldn't it be positive too?
• Apr 1st 2014, 05:11 PM
hollywood
Re: Could you check the graph for an equation?
That's right. So you would need to look at other points, like say (-1,1).

- Hollywood
• Apr 1st 2014, 05:21 PM
canyouhelp
Re: Could you check the graph for an equation?
Quote:

Originally Posted by hollywood
That's right. So you would need to look at other points, like say (-1,1).

- Hollywood

Okay..At (-1,1) the slope should be negative and the third option would fit that. right?
• Apr 1st 2014, 05:23 PM
hollywood
Re: Could you check the graph for an equation?
Yes, that's correct.

- Hollywood