Finding the Angle Between Two Vectors A & B

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SUMMARY

The discussion focuses on calculating the angle between two vectors A = -2i + 5j and B = 2i + 3j using the vector product. The vector product, denoted as A x B, is established as a vector that can be calculated using a determinant. The angle between the vectors can be derived from the equation |A x B| = |A||B|sin(θ), where θ represents the angle between the vectors. The confusion regarding the negative sign in the calculation is clarified, emphasizing that the vector product results in a vector, not a scalar.

PREREQUISITES
  • Understanding of vector notation and operations
  • Familiarity with the concept of vector products
  • Knowledge of determinants in linear algebra
  • Basic trigonometry, specifically sine functions
NEXT STEPS
  • Study the properties of vector products in three-dimensional space
  • Learn how to calculate determinants for 2x2 and 3x3 matrices
  • Explore the relationship between vector magnitudes and angles using the law of cosines
  • Practice solving problems involving angles between vectors using the formula |A x B| = |A||B|sin(θ)
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Students in physics or mathematics, particularly those studying vector calculus, as well as educators looking for clear explanations of vector operations and their applications.

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Homework Statement



Two vectors are given by A = -2 i + 5 j and B = 2 i + 3 j
Also find the angle between them

Homework Equations



Not really sure but from my book i get A x B = -B x A

The Attempt at a Solution



the answer is -16, but I'm confused I thought that it should look like -6 + 10 but why is it minus ten?

How would I use this to find the angle?
 
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Do you know how to set up a determinant for vector product? From the determinant you can easilly calculate the product vector. Remember the result of a vector product is always a vector.

When you know the vector product you can find the angle from

(AxB)=|A||B|sin(A,B)

Where A and B are the 2 vectors, (AxB) is the vector product and |A|/|B| are the lenghts of the vectors.
 

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