How do you find the magnitude and direction of the vector difference a = 400i + 300j and b = 500i + 200j?

To find the vector difference of a and b, we will subtract vector b from vector a:

a – b = (400i + 300j) – (500i + 200j)

First, we can break this down into its components:

  • i-components: 400 – 500 = -100
  • j-components: 300 – 200 = 100

So the resulting vector difference is:

a – b = -100i + 100j

Next, to find the magnitude of this vector, we can use the formula:

|v| = √(x² + y²)

Where x and y are the components of the vector. In our case:

|v| = √((-100)² + (100)²)

This simplifies to:

|v| = √(10000 + 10000) = √20000 = 141.42

Now, we will find the direction of the vector using the tangent function. The angle θ can be found with:

tan(θ) = y/x = 100 / (-100)

This gives us:

tan(θ) = -1

Now we can find the angle:

θ = arctan(-1)

This corresponds to an angle of -45 degrees. Since the vector is in the second quadrant (negative i and positive j), we add 180 degrees to find the angle from the positive x-axis:

θ = -45 + 180 = 135 degrees

In conclusion, the magnitude of the vector difference a – b is approximately 141.42 and the direction is 135 degrees from the positive x-axis.

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