Dot Product Calculator

Introducing the Dot Product Calculator! Our Mathematics Master free online tool calculator computes the dot product of specified vectors, displaying the results quickly and streamlining the entire calculation process. Say goodbye to tedious manual computations and embrace the simplicity and speed of our calculator for accurate dot product solutions.

Dot Product Calculator
Vector a

Vector b

What is the Dot Product?

In mathematics, the scalar quantity that results from specified operations on the vector components is known as the dot product. The heavy dot is used to symbolize the dot product of two vectors.

Dot Product Formula

The formula to determine the dot product of two vectors, if a and b are the two vectors, is given by

\( a·b = |a|·|b|·cos(θ) \)

Where:

  • |a| and |b| are the magnitude of the vectors
  • θ is the angle between the vectors

When cosine is the proportion of the scalar product to the magnitudes of the vectors, the calculator can also be used to determine the angle between two vectors:

\( cos(θ) = \dfrac{a × b}{|a| × |b|} \)

Dot Product Properties

The dot product, also known as the scalar product, is an important operation that can be performed on vectors. Here are the properties of the dot product:

Commutative Property:

For any two vectors →a and →b, the dot product is commutative:
→a · →b = →b · →a
This means that the dot product of two vectors is independent of the order in which they are multiplied.

Distributive Property:

The dot product is distributive over vector addition and subtraction:
→a · (→b + →c) = →a · →b + →a · →c
→a · (→b – →c) = →a · →b – →a · →c
This property implies that the dot product distributes over vector addition and subtraction.

Nature of Dot Product:

The dot product is related to the angle θ between two vectors →a and →b:
If θ = 0, then →a · →b = |→a| |→b| cos θ = |→a| |→b|.
If θ = π, then →a · →b = |→a| |→b| cos θ = – |→a| |→b|.
If θ = π/2, then →a · →b = |→a| |→b| cos θ = 0.
If 0 < θ < π/2, then →a · →b > 0 (both vectors point in the same general direction).
If π/2 < θ < π, then →a · →b < 0 (both vectors point in opposite directions).

Vector Dot Product Calculator

The two main types of vector multiplication are the cross product, denoted by the symbol “×”, and the dot product, commonly known as the scalar product, represented by the symbol “,”. The crucial distinction is that the cross operation produces a vector, whereas the dot product produces a single number as its product.

How to Calculate the Dot Product of Two Vectors

The sum of the products in the cartesian coordinates of two vectors is known as a dot product. A dot product, often known as ab, is a single number rather than a vector, in contrast to the cross product.

If their dot product is zero, two vectors are orthogonal or perpendicular to one another.

Example

Example 1: Find the dot product of the vectors A and B.
A = 3i + 2j – 5k
B = -6i + 4j + 2k

We need to use the component formula for the dot product of three-dimensional vectors here,

\( a⋅b = a_1 b_1 + a_2 b_2 + a_3 b_3 \)

The dot product is:

\( a⋅b = 2(5) + 3(−6) + 4(7) = 10 − 18 + 28 = 20\)

Dot product = 20

Example 2: Calculate the dot product of: a = (2, 3, 4) and b = (5, −6, 7)

The dot product of two vectors A and B is given by the sum of the products of their corresponding components:
A · B = (3i + 2j – 5k) · (-6i + 4j + 2k)

Now, calculate the dot product:
A · B = 3(-6) + 2(4) + (-5)(2)
A · B = -18 + 8 – 10
A · B = -20

So, the dot product of vectors A and B is -20.

FAQs

How are matrices multiplied?

Matrix multiplication is not as straightforward as a scalar. The dot product creates the third matrix by joining two matrices—which need not be of the same dimension—into one. Alternatively, we can use a matrix dot product calculator.

What is the dot product of matrices?

Dot products are formed when the rows of the first matrix and the columns of the second matrix are multiplied. For example, the first step is the dot product between the first row of A and the first column of B. The member of the resulting matrix at position [0, 0] is the dot product’s output (i.e. first row, first column).

Why is the dot product considered a projection?

The dot product of vector “a” with a unit vector “u,” denoted as “a⋅u,” serves as a projection of vector “a” in the direction of “u.” In simpler terms, it quantifies the extent to which vector “a” aligns with the direction of the unit vector “u,” effectively measuring the component of “a” that points in the same direction as “u.”

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