WAEC WAEC Nigeria General Mathematics

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(Vectors in a Plane)

Vector Magnitude

Vector Magnitude in a Plane

What is a Vector?

A vector in a plane is a quantity that has both magnitude (size) and direction. It is often represented as an arrow where the length indicates the magnitude and the arrowhead shows the direction.

Understanding Vector Magnitude

The magnitude of a vector is its length. For a vector v=(x,y)\mathbf{v} = (x, y) in the Cartesian plane, the magnitude is calculated using the Pythagorean theorem:

v=x2+y2|\mathbf{v}| = \sqrt{x^2 + y^2}

Steps to Calculate Vector Magnitude

  1. Identify the components: Find the xx and yy components of the vector.
  2. Square each component: Calculate x2x^2 and y2y^2.
  3. Add the squares: Sum the squared components.
  4. Find the square root: Take the square root of the sum to find the magnitude.

Examples

Example 1: Calculate the Magnitude of a Vector

Worked Example

Find the magnitude of the vector v=(3,4)\mathbf{v} = (3, 4).

Example 2: Calculate the Magnitude of a Vector

Worked Example

Find the magnitude of the vector u=(2,6)\mathbf{u} = (-2, 6).

Tuity Tip

Hover me!

Tip: Always remember to square the components before adding them. This ensures that the magnitude is always a non-negative value.

Check Your Work: Double-check your calculations, especially when squaring negative numbers, to avoid mistakes.

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