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Re: Math: Coordinate Geometry [#permalink]
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09 Feb 2013, 02:11



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Re: Math: Coordinate Geometry [#permalink]
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09 Feb 2013, 03:45
HI Bunuel, As karishma has also mentioned that a line with ve slope can also be present in 1st quadrant than how can we be so sure that it is intersecting in 2nd quadrant,
Moreover as per the theory it must intersect in 2nd and 4th quadrant ...than as per statement 1 there are two possibilities.....line intersecting in in quad 2 and 4.....But we must have only one answer form the statement, for it to be correct answer..................
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Re: Math: Coordinate Geometry [#permalink]
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09 Feb 2013, 03:53
Archit143 wrote: HI Bunuel, As karishma has also mentioned that a line with ve slope can also be present in 1st quadrant than how can we be so sure that it is intersecting in 2nd quadrant,
Moreover as per the theory it must intersect in 2nd and 4th quadrant ...than as per statement 1 there are two possibilities.....line intersecting in in quad 2 and 4.....But we must have only one answer form the statement, for it to be correct answer..................
Archit No, that's not what she said. If the slope of a line is negative, line WILL intersect quadrants II and IV in ANY case. If X and Y intersects are positives, line ALSO intersects the quadrant I, if negative line ALSO intersects the quadrant quadrant III.
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Re: Math: Coordinate Geometry [#permalink]
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09 Feb 2013, 22:53
Archit143 wrote: So for a question where it is given that slope is 1/6, Than how can be sure that line intersects 2nd quad, I found this question on GMAT prep...... intherectangularcoordinatesystemshownabovedoesthe90635.htmlArchit Since the slope is negative, the line will intersect the 2nd and 4th quadrant. We are talking about a line, not a line segment. A line extends indefinitely on both ends. The top end of the line will extend to intersect the 2nd quadrant under all circumstances. Attachment:
Ques3.jpg [ 7.76 KiB  Viewed 3523 times ]
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Re: Math: Coordinate Geometry [#permalink]
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10 Feb 2013, 04:16
Karishma, thats what i wanted to ask....In question it asks about whether the line is intersecting 2nd quadrant....Answer is Yes it does, but at the same time it may lie in 1st quadrant also as explained by you....I think i am badly confused on this....
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10 Feb 2013, 04:23



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Re: Math: Coordinate Geometry [#permalink]
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10 Feb 2013, 06:27
Thanks Bunuel.... I got it..
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Re: Math: Coordinate Geometry [#permalink]
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06 Apr 2013, 08:06
Hi Bunuel, Thanks for the consolidated , yet elaborate content for the topic at one place. I would be glad , if you can tell me as to , how did you arrive at the formula for the vertex of a parabola. I find it difficult to remember formulas and if there is a easy way to arrive at the formula itself , then would prefer to know that too , so it helps in case I forget the formula. Appreciate any help on this. Thanks, Jyothi
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Re: Math: Coordinate Geometry [#permalink]
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Re: Math: Coordinate Geometry [#permalink]
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05 Aug 2013, 10:19
Hi bunuel, firstly i want to thank for the explanations you provide to questions because most of them are pretty conceptual and healthy to understand. Secondly, i wished i was more thorough with my concepts in coordinate geometry specifically PARABOLA. i had seen two parabola questions when i took the test & both were quite hard unfortunately, had to end up guessing. Have yu posted any questions related to Parabola ??



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Re: Math: Coordinate Geometry [#permalink]
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25 Nov 2014, 23:21
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The angle of inclination of a line with slope 1 is 45 degrees. I know that the angle for a line of slope 2 is not 90 degree, but i do not know why not. Please help



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Re: Math: Coordinate Geometry [#permalink]
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04 May 2015, 11:45
All of the formulas in this post using division are messed up. I believe the formatting or something has changed and caused this error. Please fix this! See the current formula for the slop as an example.



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Re: Math: Coordinate Geometry [#permalink]
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Re: Math: Coordinate Geometry [#permalink]
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10 May 2016, 20:47
Thanks Bunuel this is my weak subject for the gmat.
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Re: Math: Coordinate Geometry [#permalink]
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22 Mar 2017, 12:14
Can you please explain here;
To answer, we must find the slope of each line and then check to see if one slope is the negative reciprocal of the other or if their product equals to 1. SlopeAB=5−199−48=−14−39=0.358SlopeAB=5−199−48=−14−39=0.358
SlopeCD=24−422−31=20−9=−2.22
The formula of the slope of two given coordinates are y2y1 / x2x1
However in some questions, 2nd coordinates (x2 y2)s are subtracted from 1sts (x1 y1) and in some, other way around. Can you please clarify what do we take into account concerning this formula?



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Re: Math: Coordinate Geometry [#permalink]
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22 Mar 2017, 22:52
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mesutthefail wrote: Can you please explain here;
To answer, we must find the slope of each line and then check to see if one slope is the negative reciprocal of the other or if their product equals to 1. SlopeAB=5−199−48=−14−39=0.358SlopeAB=5−199−48=−14−39=0.358
SlopeCD=24−422−31=20−9=−2.22
The formula of the slope of two given coordinates are y2y1 / x2x1
However in some questions, 2nd coordinates (x2 y2)s are subtracted from 1sts (x1 y1) and in some, other way around. Can you please clarify what do we take into account concerning this formula? Hi, This is a mathematical rule. You can write ab = (ba). Did you get this rule?? Now, in a similar way if you take  sign common from both numerator and denominator of y2y1 / x2x1, you will get (y1y2)/(x1x2). I hope you are aware of the rule that  signs can be cancelled out both a numerator and denominator. So, we will be left with the formula, Slope = (y1y2)/(x1x2). I hope that makes sense.
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Re: Math: Coordinate Geometry [#permalink]
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23 Mar 2017, 03:22
mesutthefail wrote: Can you please explain here;
To answer, we must find the slope of each line and then check to see if one slope is the negative reciprocal of the other or if their product equals to 1. SlopeAB=5−199−48=−14−39=0.358SlopeAB=5−199−48=−14−39=0.358
SlopeCD=24−422−31=20−9=−2.22
The formula of the slope of two given coordinates are y2y1 / x2x1
However in some questions, 2nd coordinates (x2 y2)s are subtracted from 1sts (x1 y1) and in some, other way around. Can you please clarify what do we take into account concerning this formula? They are both the same. \(Slope = \frac{(y2  y1)}{(x2  x1)} = \frac{(y1  y2)}{(x1  x2)}\) Take an example: (x1, y1) = (2, 3) (x2, y2) = (5, 10) \(Slope = \frac{(y2  y1)}{(x2  x1)} = \frac{10  3}{5  2} = \frac{13}{3}\) \(Slope = \frac{(y1  y2)}{(x1  x2)} = \frac{3 (10)}{2  5} = \frac{13}{3}\)
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Re: Math: Coordinate Geometry [#permalink]
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01 Sep 2017, 23:22
Hello Bunuel, Thanks a lot for the article. I have one doubt . Is it that a line with negative slope would definitely pass through Quadrant 2 and 4, and would pass through 1 or 3 depending on the value of x and y intersects?




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