Math Problem Statement

Given vectors \( \vec{a} = -\hat{i} + 2\hat{j} - 3\hat{k} \) and \( \vec{b} = 2\hat{i} - 3\hat{j} + 5\hat{k} \), calculate the dot product \( \vec{a} \cdot \vec{b} \).

Solution

To solve for the dot product of vectors a\vec{a} and b\vec{b}, we can use the formula:

ab=axbx+ayby+azbz\vec{a} \cdot \vec{b} = a_x \cdot b_x + a_y \cdot b_y + a_z \cdot b_z

where:

  • a=i^+2j^3k^\vec{a} = -\hat{i} + 2\hat{j} - 3\hat{k},
  • b=2i^3j^+5k^\vec{b} = 2\hat{i} - 3\hat{j} + 5\hat{k}.

Step 1: Identify the components

From the vectors, we have:

  • ax=1a_x = -1, ay=2a_y = 2, az=3a_z = -3,
  • bx=2b_x = 2, by=3b_y = -3, bz=5b_z = 5.

Step 2: Calculate each component of the dot product

axbx=(1)2=2a_x \cdot b_x = (-1) \cdot 2 = -2 ayby=2(3)=6a_y \cdot b_y = 2 \cdot (-3) = -6 azbz=(3)5=15a_z \cdot b_z = (-3) \cdot 5 = -15

Step 3: Sum the results

ab=2615=23\vec{a} \cdot \vec{b} = -2 - 6 - 15 = -23

Final Answer

ab=23\vec{a} \cdot \vec{b} = -23

Would you like more details or have any questions?

Related Questions

  1. What is the geometric interpretation of the dot product result being negative?
  2. How do you find the angle between two vectors using their dot product?
  3. What would the cross product a×b\vec{a} \times \vec{b} look like?
  4. How does changing the magnitude of a vector affect its dot product with another vector?
  5. How does the dot product help determine if two vectors are perpendicular?

Tip: The dot product of two vectors is zero if they are perpendicular, since cos(90)=0\cos(90^\circ) = 0.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Vector Algebra
Dot Product

Formulas

\( \vec{a} \cdot \vec{b} = a_x \cdot b_x + a_y \cdot b_y + a_z \cdot b_z \)

Theorems

Dot Product Formula

Suitable Grade Level

Grades 10-12