Math Problem Statement

Compute ⟨5, 1, 2⟩ × ⟨−2, 1, −3⟩.

Solution

The cross product of two vectors a1,a2,a3\langle a_1, a_2, a_3 \rangle and b1,b2,b3\langle b_1, b_2, b_3 \rangle is given by:

a1,a2,a3×b1,b2,b3=a2b3a3b2,a3b1a1b3,a1b2a2b1\langle a_1, a_2, a_3 \rangle \times \langle b_1, b_2, b_3 \rangle = \langle a_2b_3 - a_3b_2, a_3b_1 - a_1b_3, a_1b_2 - a_2b_1 \rangle

Given the vectors 5,1,2\langle 5, 1, 2 \rangle and 2,1,3\langle -2, 1, -3 \rangle, let's compute each component:

  1. First Component: a2b3a3b2=(1)(3)(2)(1)=32=5a_2b_3 - a_3b_2 = (1)(-3) - (2)(1) = -3 - 2 = -5
  2. Second Component: a3b1a1b3=(2)(2)(5)(3)=4+15=11a_3b_1 - a_1b_3 = (2)(-2) - (5)(-3) = -4 + 15 = 11
  3. Third Component: a1b2a2b1=(5)(1)(1)(2)=5+2=7a_1b_2 - a_2b_1 = (5)(1) - (1)(-2) = 5 + 2 = 7

Thus, the cross product 5,1,2×2,1,3\langle 5, 1, 2 \rangle \times \langle -2, 1, -3 \rangle is:

5,11,7\langle -5, 11, 7 \rangle

Would you like further details or explanations?

Here are 5 related questions for further exploration:

  1. What is the magnitude of the cross product vector 5,11,7\langle -5, 11, 7 \rangle?
  2. How do you verify if two vectors are parallel using their cross product?
  3. What is the geometric significance of the cross product?
  4. How can you determine the area of the parallelogram formed by two vectors using their cross product?
  5. What is the relationship between the cross product and the sine of the angle between two vectors?

Tip: The direction of the cross product follows the right-hand rule, which helps determine the orientation of the resulting vector.

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Math Problem Analysis

Mathematical Concepts

Vector Algebra
Cross Product
3D Vectors

Formulas

Cross product formula: ⟨a₁, a₂, a₃⟩ × ⟨b₁, b₂, b₃⟩ = ⟨a₂b₃ - a₃b₂, a₃b₁ - a₁b₃, a₁b₂ - a₂b₁⟩

Theorems

Right-hand rule
Cross product theorem for vector orthogonality

Suitable Grade Level

Grades 10-12