218k views
1 vote
Determine whether the lines x = p +su and x = q + tv intersect.p = −1, 8, 1 , q = 8, 8, 0 , u = 1, 8, −1 , v = −1, 1, 0,

The two lines intersect. The two lines do not intersect. Find the point of intersection. (If there is no solution, enter NO SOLUTION.)

[x, y, z] =

User Sergiom
by
7.2k points

1 Answer

2 votes

Final answer:

The point of intersection for the given lines is (-136/27, 13/3, 11/3).

Step-by-step explanation:

In order to determine whether the lines x = p + su and x = q + tv intersect, we need to find the values of s and t that make the equations true. We can do this by setting the equations equal to each other:

p + su = q + tv

Now, we can isolate the variables:

  1. s = (q - p + tv) / u
  2. t = (p - q + su) / v

Substituting the given values, we have:

  1. s = (8 - (-1) + (−1)v) / 1
  2. t = ((−1) - 8 + (1)(8u)) / (-1)

Simplifying each expression, we get:

  1. s = (9 - v) / 1
  2. t = (−9 + 8u) / (-1)

Since we want the lines to intersect, there must be values of s and t that satisfy both equations. By substituting the expressions for s and t in terms of v and u into the equation for x, we can find the point of intersection:

  1. x = p + su = -1 + (9 - v) / 1 u = 8 - v
  2. x = q + tv = 8 + (−9 + 8u) / (-1) v = 8u - 17

By setting the expressions for x equal to each other, we have:

8 - v = 8u - 17

Now, we can solve for v in terms of u:

v = 8u - 25

Since u = 8 - v, we can substitute that expression into the equation:

v = 8(8 - v) - 25

Expanding and simplifying, we get:

v = 64 - 8v - 25

Combining like terms, we have:

9v = 39

Dividing both sides by 9, we find:

v = 13/3

Substituting this value back into the equation v = 8u - 25, we can solve for u:

13/3 = 8u - 25

Adding 25 to both sides, we have:

88/3 = 8u

Dividing both sides by 8, we get:

11/3 = u

Now that we have the values of u and v, we can substitute them back into either of the expressions for x to find the point of intersection. Substituting into x = p + su, we get:

x = -1 + (9 - 13/3)(11/3) = -1 + (9 - 143/9)/3 = -1 + 72/9 - 143/27 = -1 + 8 - 143/27 = -136/27

Therefore, the point of intersection is (-136/27, 13/3, 11/3).

User Tonyjosi
by
7.7k points