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#1 2006-11-08 03:15:00

unique
Member
Registered: 2006-10-04
Posts: 419

Correct

Find the distance between the point (3,1) and the line y = x - 4

i did like this :

y = -2x + b < equation
1 = -2(2) + b < use (3,1)
1 = -6 + b < add 6
7 = b
y = -2x + 7 < completed equation
THAN
x - 4 = -2x + 7 < substitution
add 4 both sides
x = -2 + 11
3x = -2 + 11
3x = 9
x = 9/3 < solved for x
THAN
y = -2 (9/3) + 7
y = -6 + 7
y = 1 < solved for y
THAN distance formula
D = sqrt( ( (x2 - x1)^2 + (y2 - y1)^2 )
(3,1) and (3,1)
D = sqrt ( (3 - 3)^2 + (1 - 1)^2 )
D = sqrt( 0 + 0)
D = 0 < solved
answer is zero
correct?up


Desi
Raat Key Rani !

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#2 2006-11-08 06:10:07

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,588

Re: Correct

.
             .
             .          /
           o .         /
            o.        /
             o       /
             .o     /
             . o   /
             .  . /
             ....o...........
             .  / o
             . /   o
             ./     o
             /       o
             .        o
             .         o
             .
             .     square root of 2
             .     one down and one right.


igloo myrtilles fourmis

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#3 2006-11-08 07:42:26

unique
Member
Registered: 2006-10-04
Posts: 419

Re: Correct

so am i right?


Desi
Raat Key Rani !

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#4 2016-12-15 19:54:22

Monox D. I-Fly
Member
Registered: 2015-12-02
Posts: 891

Re: Correct

No. The distance of a point and a line is 0 if the point is in the line. In your question, however, the coordinate (3,1) doesn't satisfy the equation y = x - 4 because 3 - 4 ≠ 1.

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#5 2016-12-16 15:13:47

Mathegocart
Member
Registered: 2012-04-29
Posts: 1,884

Re: Correct

Problem solved, after 10 years..


The integral of hope is reality.

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#6 2016-12-16 15:28:22

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Correct

Hi;

John gave an answer in post #2 also.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#7 2016-12-17 12:15:36

Monox D. I-Fly
Member
Registered: 2015-12-02
Posts: 891

Re: Correct

Well, I answered post #3, since he seemed to not understand implicit answers.

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#8 2016-12-17 12:33:19

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Correct

No problem.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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