# Math Is Fun Forum

Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫  π  -¹ ² ³ °

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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
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
correct?

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

so am i right?

Desi
Raat Key Rani !

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

Monox D. I-Fly
Member
From: Indonesia
Registered: 2015-12-02
Posts: 2,000

### 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.

Actually I never watch Star Wars and not interested in it anyway, but I choose a Yoda card as my avatar in honor of our great friend bobbym who has passed away.
May his adventurous soul rest in peace at heaven.

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

Mathegocart
Member
Registered: 2012-04-29
Posts: 2,199

### Re: Correct

Problem solved, after 10 years..

The integral of hope is reality.
May bobbym have a wonderful time in the pearly gates of heaven.
He will be sorely missed.

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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
From: Indonesia
Registered: 2015-12-02
Posts: 2,000

### Re: Correct

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

Actually I never watch Star Wars and not interested in it anyway, but I choose a Yoda card as my avatar in honor of our great friend bobbym who has passed away.
May his adventurous soul rest in peace at heaven.

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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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