Proving Law of Sines Using Vector Cross Product

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SUMMARY

The discussion focuses on proving the Law of Sines using the vector cross product, specifically through the area of a triangle. The key equation referenced is |A||C|sin(θ) = (a2c3 − a3c2) + (a3c1 − a1c3) + (a1c2 − a2c1). The user initially struggled with the proof but ultimately resolved the issue independently. The hint provided emphasizes the relationship A + B + C = 0, which is crucial for the proof.

PREREQUISITES
  • Understanding of vector cross products
  • Familiarity with triangle area calculations
  • Knowledge of the Law of Sines
  • Basic vector algebra
NEXT STEPS
  • Study vector cross product properties in depth
  • Explore geometric interpretations of the Law of Sines
  • Investigate alternative proofs of the Law of Sines
  • Learn about the relationship between vectors and triangle geometry
USEFUL FOR

Students studying geometry, mathematics educators, and anyone interested in vector applications in proving trigonometric laws.

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Homework Statement


Prove the law of sines using a vector cross product. (Hint, consider the area of the triangle and that A+B+C=0.)


Homework Equations


|A||C|sin ( θ ) = (a2c3 − a3c2) + (a3c1 − a1c3) + (a1c2 − a2c1)


The Attempt at a Solution


The farthest I went is to show .5 |a||c|sin \theta .. I've tried some other things but then it just turns out to be some incomprehensible mess. I chose C to be my longest side. I simply do not know what to do; I've exhausted both forms of the cross product I know, and it appers to go nowhere.
 
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Never mind, I figured it out. Thanks anyway!
 

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