Vector Addition, Subtraction, and Scalar Multiplication Math Example 1

Follow the full solution, then compare it with the other examples linked below.

Example 1

easy
If u=โŸจ3,โˆ’1โŸฉ\mathbf{u} = \langle 3, -1 \rangle and v=โŸจ1,4โŸฉ\mathbf{v} = \langle 1, 4 \rangle, find 2uโˆ’v2\mathbf{u} - \mathbf{v}.

Solution

  1. 1
    Step 1: 2u=โŸจ6,โˆ’2โŸฉ2\mathbf{u} = \langle 6, -2 \rangle.
  2. 2
    Step 2: 2uโˆ’v=โŸจ6โˆ’1,โˆ’2โˆ’4โŸฉ=โŸจ5,โˆ’6โŸฉ2\mathbf{u} - \mathbf{v} = \langle 6 - 1, -2 - 4 \rangle = \langle 5, -6 \rangle.
  3. 3
    Check: Each component is 2uiโˆ’vi2u_i - v_i โœ“

Answer

โŸจ5,โˆ’6โŸฉ\langle 5, -6 \rangle
Scalar multiplication scales each component, then subtraction is done component-wise. Linear combinations of vectors like au+bva\mathbf{u} + b\mathbf{v} are fundamental in linear algebra.

About Vector Addition, Subtraction, and Scalar Multiplication

Vectors are added and subtracted component by component. Scalar multiplication multiplies each component of a vector by a number. If u=โŸจu1,u2โŸฉ\mathbf{u} = \langle u_1, u_2 \rangle and v=โŸจv1,v2โŸฉ\mathbf{v} = \langle v_1, v_2 \rangle, then u+v=โŸจu1+v1,u2+v2โŸฉ\mathbf{u} + \mathbf{v} = \langle u_1 + v_1, u_2 + v_2 \rangle and ku=โŸจku1,ku2โŸฉk\mathbf{u} = \langle ku_1, ku_2 \rangle.

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