Questions   
Sort: 
 #1
avatar
0
Apr 24, 2023
 #1
avatar+16 
0

To find the perpendicular distance from the given line to the point (2,1,7), we need to find a point on the line that is closest to the given point. This point will be on the line connecting the given point and the line, and will be the point where a perpendicular line from the given point intersects the line.

Next Employee Portal Login

Let's first find the vector equation of the line:
r(t) = (-1,4,3) + t(4,-10,10)

 

Now we need to find the point on this line closest to the given point (2,1,7). Let P be this point. The vector connecting P to (2,1,7) will be perpendicular to the line. So, we can find P by projecting the vector between (2,1,7) and (-1,4,3) onto the direction vector of the line.

 

The direction vector of the line is d = (4,-10,10). So, we can find the projection of the vector between (2,1,7) and (-1,4,3) onto d as follows:

proj_d(v) = ((v · d) / ||d||^2) d,

where · denotes the dot product, and ||d|| is the magnitude of d.

v = (2-(-1), 1-4, 7-3) = (3,-3,4)

||d|| = sqrt(4^2 + (-10)^2 + 10^2) = sqrt(216) = 6*sqrt(6)

 

So, proj_d(v) = ((34 - 3(-10) + 410) / (6sqrt(6))^2) (4,-10,10) = (37/216) (4,-10,10) = (37/54) (2,-5,5)

The point P on the line closest to (2,1,7) is given by:

P = (-1,4,3) + proj_d(v) = (-1,4,3) + (37/54) (2,-5,5) = (-1 + 37/27, 4 - 185/54, 3 + 185/54) = (4/27, 83/54, 229/54)

 

Now we can find the distance between P and (2,1,7):

dist = ||P - (2,1,7)|| = ||(4/27 - 2, 83/54 - 1, 229/54 - 7)|| = ||(22/27, 29/54, -97/54)|| = sqrt((22/27)^2 + (29/54)^2 + (-97/54)^2) = sqrt(2325/1458) = (5/6) sqrt(93)

Therefore, the perpendicular distance from the line to the point (2,1,7) is (5/6) sqrt(93).

Apr 24, 2023
 #1
avatar+33666 
+1
Apr 24, 2023
 #1
avatar
0

 

Find the distance between the x-intercept and the y-intercept of the graph of the equation 3x - 7y = 21 + 2x - 5y

 

                                                       3x - 7y = 21 + 2x - 5y  

 

Combine like terms.                         –7y + 5y  =  2x – 3x + 21  

 

                                                         –2y  =  –x + 21 

 

Multiply both sides by –1

this isn't necessary but it 

makes it easy to work with.  

Easier for me, anyway, LOL.                2y  =  x – 21  

 

Set y = 0 and solve for x                                 x  =  21         That's your x-intercept.  

Set x = 0 and solve for y                                 y  =  –10.5    That's your y-intercept. 

 

Those are the values of the two legs of a right triangle, with the origin being the right angle. 

If you draw it on a graph, it's obvious.  

 

The line between the x- and y- intercepts is the hypotenuse of that right triangle. 

 

Pythagoras' Theorem                         c2  =  (21)2 + (–10.5)2   

 

                                                           c2  =  441 + 110.25  =  551.25   

 

I used my calculator to

get this square root.                            c  =  23.48  

.

Apr 24, 2023
Apr 23, 2023

1 Online Users