Math Problem Statement

Given that a=⟨−2,5⟩ and b=⟨4,1⟩ , draw a graphical representation of 2a−3b . Then find the resultant vector algebraically to verify your resultant.

Solution

To solve this, we’ll go through two main steps: (1) calculating the vector 2a3b2\mathbf{a} - 3\mathbf{b} algebraically, and (2) graphically representing this vector. Let's begin.

Step 1: Calculate 2a3b2\mathbf{a} - 3\mathbf{b} Algebraically

Given: a=2,5\mathbf{a} = \langle -2, 5 \rangle b=4,1\mathbf{b} = \langle 4, 1 \rangle

  1. Multiply a\mathbf{a} by 2: 2a=22,5=4,102\mathbf{a} = 2 \cdot \langle -2, 5 \rangle = \langle -4, 10 \rangle

  2. Multiply b\mathbf{b} by 3: 3b=34,1=12,33\mathbf{b} = 3 \cdot \langle 4, 1 \rangle = \langle 12, 3 \rangle

  3. Calculate 2a3b2\mathbf{a} - 3\mathbf{b}: 2a3b=4,1012,32\mathbf{a} - 3\mathbf{b} = \langle -4, 10 \rangle - \langle 12, 3 \rangle =412,103= \langle -4 - 12, 10 - 3 \rangle =16,7= \langle -16, 7 \rangle

So, the resultant vector is: 2a3b=16,72\mathbf{a} - 3\mathbf{b} = \langle -16, 7 \rangle

Step 2: Graphical Representation

  1. Draw vectors a\mathbf{a} and b\mathbf{b}: Represent a=2,5\mathbf{a} = \langle -2, 5 \rangle and b=4,1\mathbf{b} = \langle 4, 1 \rangle on a coordinate system.

  2. Scale a\mathbf{a} and b\mathbf{b} appropriately: Draw 2a2\mathbf{a} by extending a\mathbf{a} to twice its length, and 3b3\mathbf{b} by extending b\mathbf{b} to three times its length.

  3. Subtract the scaled vectors: To get 2a3b2\mathbf{a} - 3\mathbf{b}, place the vector 3b3\mathbf{b} with its tail at the head of 2a2\mathbf{a}, but in the opposite direction, since we are subtracting 3b3\mathbf{b}.

  4. Draw the resultant vector 16,7\langle -16, 7 \rangle: The vector 16,7\langle -16, 7 \rangle can now be represented on the graph, originating from the origin to show the resultant direction and magnitude.

Would you like a graphical illustration, or do you have any questions about these steps?


Additional Questions to Consider

  1. What are the magnitudes of vectors a\mathbf{a}, b\mathbf{b}, and 2a3b2\mathbf{a} - 3\mathbf{b}?
  2. How would the direction of the resultant vector change if the sign in 2a3b2\mathbf{a} - 3\mathbf{b} was reversed to 2a+3b2\mathbf{a} + 3\mathbf{b}?
  3. How does vector scaling affect the angle of the resultant vector relative to the x-axis?
  4. What other applications could benefit from calculating vector differences?
  5. How could this vector result be visualized in three dimensions if a third component were added?

Tip:

Always check each component step-by-step to avoid calculation errors when adding or subtracting vectors algebraically.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Vector Algebra
Graphical Representation

Formulas

2a - 3b = ⟨2(-2) - 3(4), 2(5) - 3(1)⟩

Theorems

Vector Addition and Subtraction

Suitable Grade Level

Grades 9-12