Math Problem Statement

3.2.1. Decompose a 2D vector trigonometrically

Give the formulas for the x and y

components of the vector 𝐴𝐵$$$$$⃗ when the

angle 𝛼 with the positive x-axis and the

length l are given.

Decompose a 2D vector trigonometrically. Give the formulas for the x and y components of the vector AB⃗ when the angle α with the positive x-axis and the length l are given.

Solution

To decompose the 2D vector AB\vec{AB} trigonometrically into its xx- and yy-components, we use the following approach:

Given:

  • ll: the magnitude (length) of the vector AB\vec{AB}
  • α\alpha: the angle the vector makes with the positive xx-axis.

Formulas for components:

  • xx-component: ABx=lcos(α)AB_x = l \cdot \cos(\alpha)
  • yy-component: ABy=lsin(α)AB_y = l \cdot \sin(\alpha)

Here:

  • ll is the magnitude of the vector AB\vec{AB}.
  • α\alpha is the angle of the vector with respect to the positive direction of the xx-axis.
  • The cosine and sine functions give us the respective components along the xx- and yy-axes.

Would you like further details or clarifications on this topic?

5 related questions:

  1. How do we calculate the magnitude of a vector if only the components are given?
  2. What happens to the components when α\alpha is greater than 9090^\circ?
  3. Can we derive these component formulas using unit vectors?
  4. How does the direction of the vector affect its xx- and yy-components?
  5. What is the relationship between the angle α\alpha and the direction of the vector?

Tip:

Always make sure the angle α\alpha is measured from the positive xx-axis and in the correct direction (usually counterclockwise) to avoid sign errors in the components.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Vector Decomposition
2D Geometry

Formulas

x-component: AB_x = l * cos(α)
y-component: AB_y = l * sin(α)

Theorems

Trigonometric decomposition of vectors

Suitable Grade Level

Grades 9-12