Cross product and Dot product problem

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SUMMARY

The discussion centers on calculating the tangent of the angle (tan(θ)) between two vectors, v and w, given their cross product v x w = <5, 5, -2> and dot product v * w = 6. The correct approach involves using the equations |v x w| = |v| |w| sin(θ) and v * w = |v| |w| cos(θ). By dividing the two equations, the absolute values cancel, allowing for the determination of tan(θ) as the ratio of the magnitudes of the cross product to the dot product.

PREREQUISITES
  • Understanding of vector operations, specifically cross product and dot product.
  • Familiarity with trigonometric identities, particularly relating to angles between vectors.
  • Knowledge of vector magnitude calculations.
  • Basic understanding of unit vectors and the right-hand rule.
NEXT STEPS
  • Study vector operations in depth, focusing on cross product and dot product definitions.
  • Learn how to calculate the magnitude of a vector and its implications in vector mathematics.
  • Explore trigonometric functions in the context of vector angles, particularly tan(θ).
  • Investigate the right-hand rule and its applications in determining vector orientations.
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Students studying physics or mathematics, particularly those focusing on vector calculus and geometry, as well as educators teaching these concepts.

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Homework Statement



if v x w = <5,5,-2>
(v cross w)

and

v * w = 6
(v dot w)

then what is the tan(θ) between the two vectors v and w?


The Attempt at a Solution



well I was thinking v x w = |v||w|sinθ
as well as v dot w (v*w) = |v|w|cosθ

divide one equation by the other and the absolute values on the right cancel out,
but then you get a vector divided by a number on the left side equals tanθ

is this how you do this problem?
 
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You have a problem with the first equation in your attempt at solution. It should read:
|v × w| = |v| |w| sinθ

You are right that v × w is a vector, and the correct equation for it would be:
v × w = |v| |w| sinθ n
where n is the unit vector perpendicular to both v and w given by the right-hand rule.
 
To expand on what Jolb said, since you're given that v x w = <5, 5, -2>, you have enough information to find |v x w|.
 

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