Vector Addition, Subtraction, and Scalar Multiplication Math Example 4

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

Example 4

easy
Compute โˆ’3โŸจ2,โˆ’4โŸฉ-3\langle 2, -4 \rangle.

Solution

  1. 1
    โˆ’3โ‹…โŸจ2,โˆ’4โŸฉ=โŸจโˆ’6,12โŸฉ-3 \cdot \langle 2, -4 \rangle = \langle -6, 12 \rangle.
  2. 2
    Each component is multiplied by โˆ’3-3.

Answer

โŸจโˆ’6,12โŸฉ\langle -6, 12 \rangle
Negative scalar multiplication reverses the direction of the vector while scaling its magnitude by โˆฃโˆ’3โˆฃ=3|{-3}| = 3.

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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