Finding the Point of Intersection and Acute Angle between Two Lines

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SUMMARY

The discussion centers on finding the point of intersection and the acute angle between two lines represented in vector form: r=(a,b,c)+t(d,e,f) and q=(h,i,j)+s(k,l,m). The lines intersect if their parametric equations yield the same x, y, and z values, leading to a system of three equations to solve for parameters t and s. The acute angle between the two lines can be determined using the dot product of their direction vectors, which are (d,e,f) and (k,l,m).

PREREQUISITES
  • Understanding of vector equations in three-dimensional space
  • Knowledge of parametric equations
  • Familiarity with solving systems of equations
  • Concept of dot product and angle between vectors
NEXT STEPS
  • Study vector equations and their geometric interpretations
  • Learn how to solve systems of equations involving multiple variables
  • Explore the dot product and its application in finding angles between vectors
  • Investigate the conditions for intersection of lines in three-dimensional space
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Students in mathematics, physics, or engineering who are learning about vector geometry, as well as educators looking for examples of line intersection and angle calculations in three-dimensional space.

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Homework Statement



Prove that the lines r=(a,b,c)+t(d,e,f) and q=(h,i,j)+s(k,l,m) intersect, and find the coordinates of their point of intersection. Also, find the acute angle between their lines

Homework Equations





The Attempt at a Solution



I have no attempt because I'm stumpped...
 
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Do you understand that "r= (a,b,c)+ t(d,e,f)" means that x= a+ td, y= b+ te, z= c+ tf for every point on that line and that "q= (h,i,j)+ s(k,l,m)" means that x= h+ sk, y= i+ sl, z= j+ sm for every point on THAT line. If the two lines intersect then, at the point of intersection they have the same x, y, z values: x= a+ td= h+ sk, y= b+ te= i+ sl, z= c+ tf= j+ sm. That gives you three equations to solve for t and s.

Of course, typically, you can use two of those equations to find t and s and the check in the third to see if they work. Typically, two lines in 3 dimensions do NOT intersect.
 
Ok, I've managed to get the point of intersection from that, thankyou. But what about the acute angle between them?
 

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