Co-Ordinate geometry(Fundamentals)..

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Co-Ordinate geometry(Fundamentals)..

by vishubn » Sat Sep 27, 2008 11:18 pm
Hi

in one of the forum i read the below statement

When x intercept is positive and slope is also positive then y-intercept has to be negative.

i request if anyone could explain this and also if there is nething more on the same line to understand


Vishu

P.s.-Ian/Stuart if u could help.... its much appreciated :)
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Re: Co-Ordinate geometry(Fundamentals)..

by Morgoth » Sun Sep 28, 2008 3:28 am
vishubn wrote:Hi

in one of the forum i read the below statement

When x intercept is positive and slope is also positive then y-intercept has to be negative.

i request if anyone could explain this and also if there is nething more on the same line to understand


Vishu

P.s.-Ian/Stuart if u could help.... its much appreciated :)

Here you go:

in an equation of a line ax + by + c = 0

slope = -a/b


if slope is positive and x intercept is positive then y intercept is negative.

if slope is negative and x intercept is positive then y intercept has to be positive.

So on and so forth.

Hope this helps.

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Re: Co-Ordinate geometry(Fundamentals)..

by stop@800 » Sun Sep 28, 2008 6:48 am
An alternate approach:

without mathematics

x intercept is +ve so line is towards right side
and slope is +ve means line is rising.

If line is rising from +x axis it will never intersect y axis [as it is alraedy far and going farther]
it will only intersect y axis when extended backward so y intercept has to be -ve
vishubn wrote:Hi

in one of the forum i read the below statement

When x intercept is positive and slope is also positive then y-intercept has to be negative.

i request if anyone could explain this and also if there is nething more on the same line to understand


Vishu

P.s.-Ian/Stuart if u could help.... its much appreciated :)