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Two supports beams are modeled by the lines y=2x+10 and y=2x+15. What is the distance between these two lines ?

 Nov 5, 2016
 #1
avatar+129839 
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 y=2x+10 and y=2x+15

 

The lines have the same slope.........only their y intercepts are different.......the first line has a y intercept of 10 and the second has a y intercept of 15....so....the lines are 5 units apart

 

 

 

cool cool cool

 Nov 5, 2016
 #2
avatar+129839 
0

I totally blew this one....my answer is true if the lines are horizontal......

 

Let (0, 10)  be a point on the line y = 2x + 10

 

Now......a line perpendicular to this one will intersect the line y = 2x + 15  at right angles.....and the distance from (0,10) to the intersection of  y = 2x + 15 will lie along this perpendicular line...and the perpendicular line will have a slope of -1/2 and will contain (0,10)..and its equation will be y = (-1/)x + 10...so, .let us find the intersection point of these lines

 

2x + 15  =  (-1/2)x + 10   add (1/2)x to both sides and subtract 15 from both sides

 

2.5x  = -5     divide both sides by -2.5

 

x = -2    this is the x coordinate of the intersection of the lines.....and the y coordinate is y = 2(-2) + 15  = 11

 

So...we need to find the distance between (0,10)  and (-2, 11)    .....using the distance formula, we have

 

√[ (-2)^2 + (11 - 10)^2 ]  = √ [4 + 1]  = √5  ....and this is the distance between the beams

 

 

cool cool cool

 Nov 7, 2016

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