Do these 3D vectors intersect at the given points?

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The discussion centers on the intersection of two 3D lines represented by the parametric equations: x = 1 + 2t, y = 2 – t, z = t and x = -2 – s, y = 3 + 3s, z = 1 + 4s. The calculated parameters t = -8/5 and s = 1/5 yield inconsistent z-values, indicating that the lines do not intersect. The system of equations derived from setting the x, y, and z values equal results in an inconsistent system, confirming that the lines are skew. The user questions the accuracy of the input into WolframAlpha, but the consensus is that the lines do not intersect.

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paulfr
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If I put these 2 lines into wolframalpha.com it comes up with a solution

x = 1 + 2t , y = 2 – t , z = t ; x = -2 – s , y = 3 + 3s , z = 1 + 4s

t = -8/5 and s = 1/5 using equations for x & y

Solution; x = -11/5 y = 18/5 z = 9/5But the z values do not match so how can these lines intersect ?

Thanks for your input
 
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Setting the x, y, and z values equal, you get the system of equations
1 + 2t = -2 - s
2 - t = 3 + 3s
t = 1 + 4s

Moving the variables to one side gives this system
s + 2t = -3
3s + t = -1
4s - t = -1

Using matrix methods, this turns out to be an inconsistent system, meaning that the two lines don't intersect. Are you sure that the equations you entered into wolframalpha are the same as you posted?
 
Yes I checked the data several times
Wolframalpha's solution seems to ignore that z=t which
gives a different value than the 9/5 from z=1+4s

Perhaps there is some subtle interpretation they are making ?

The lines appear skew to me

Thanks for the comments
 

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