Question

TASK 1: Finding the Angle Between Two Vectors (6 pts)
Given the vectors:
a=<3,4>, b=<6,8>
Compute the dot product ab.

Find the magnitude of each vector |a| and |b|.

Use the formula to determine the angle between the vectors.
cos = a b||a||||b||
NOTE: Numerator is DOT PRODUCT. Denominator is MULTIPLICATION
Interpret the result: What does this angle tell us about the relationship between the vectors?

Answers

Answered by GPT-4o mini
To find the angle between the vectors \( a \) and \( b \), we will follow the steps provided.

1. **Calculate the dot product \( a \cdot b \)**:

The dot product of two vectors \( a = \langle a_1, a_2 \rangle \) and \( b = \langle b_1, b_2 \rangle \) is given by:

\[
a \cdot b = a_1b_1 + a_2b_2
\]

For our vectors \( a = \langle 3, 4 \rangle \) and \( b = \langle 6, 8 \rangle \):

\[
a \cdot b = 3 \cdot 6 + 4 \cdot 8 = 18 + 32 = 50
\]

2. **Calculate the magnitudes of each vector**:

The magnitude of a vector \( a = \langle a_1, a_2 \rangle \) is given by:

\[
|a| = \sqrt{a_1^2 + a_2^2}
\]

For vector \( a = \langle 3, 4 \rangle \):

\[
|a| = \sqrt{3^2 + 4^2} = \sqrt{9 + 16} = \sqrt{25} = 5
\]

For vector \( b = \langle 6, 8 \rangle \):

\[
|b| = \sqrt{6^2 + 8^2} = \sqrt{36 + 64} = \sqrt{100} = 10
\]

3. **Use the formula to determine the cosine of the angle \( \theta \)**:

The formula for the cosine of the angle between the vectors is:

\[
\cos(\theta) = \frac{a \cdot b}{|a| |b|}
\]

Substituting in the values we calculated:

\[
\cos(\theta) = \frac{50}{5 \cdot 10} = \frac{50}{50} = 1
\]

4. **Determine the angle \( \theta \)**:

Since \( \cos(\theta) = 1 \), we can find the angle \( \theta \):

\[
\theta = \cos^{-1}(1) = 0^\circ
\]

5. **Interpret the result**:

The angle of \( 0^\circ \) between the vectors indicates that the vectors \( a \) and \( b \) are parallel and point in the same direction. In this case, the vector \( b \) is a scalar multiple of vector \( a \) (specifically, \( b = 2a \)). This means that the two vectors share the same direction, and there is a direct proportionality between their magnitudes.

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