vector
a directed quantity, one with both magnitude and direction; the signed difference between two points
Examples of vector in the following topics:
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Vectors in Three Dimensions
- A Euclidean vector (sometimes called a geometric or spatial vector, or—as here—simply a vector) is a geometric object that has magnitude (or length) and direction and can be added to other vectors according to vector algebra.
- Vectors play an important role in physics: velocity and acceleration of a moving object and forces acting on it are all described by vectors.
- Thus the bound vector represented by is a vector of unit length pointing from the origin along the positive -axis.
- The coordinate representation of vectors allows the algebraic features of vectors to be expressed in a convenient numerical fashion.
- For example, the sum of the vectors and $(−2,0,4)$ is the vector:
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Tangent Vectors and Normal Vectors
- A vector is normal to another vector if the intersection of the two form a 90-degree angle at the tangent point.
- In order for a vector to be normal to an object or vector, it must be perpendicular with the directional vector of the tangent point.
- When you take the dot product of two vectors, your answer is in the form of a single value, not a vector.
- Tangent vectors are almost exactly like normal vectors, except they are tangent instead of normal to the other vector or object.
- These vectors can be found by obtaining the derivative of the reference vector, :
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The Cross Product
- The cross product of two vectors is a vector which is perpendicular to both of the original vectors.
- The result is a vector which is perpendicular to both of the original vectors.
- Because it is perpendicular to both original vectors, the resulting vector is normal to the plane of the original vectors.
- The magnitude of vector is equal to the area of the parallelogram made by the two original vectors.
- If you use the rules shown in the figure, your thumb will be pointing in the direction of vector , the cross product of the vectors.
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Calculus of Vector-Valued Functions
- A vector function is a function that can behave as a group of individual vectors and can perform differential and integral operations.
- A vector-valued function, also referred to as a vector function, is a mathematical function of one or more variables whose range is a set of multidimensional vectors or infinite-dimensional vectors.
- The input of a vector-valued function could be a scalar or a vector.
- Vector calculus is a branch of mathematics that covers differentiation and integration of vector fields in any number of dimensions.
- Because vector functions behave like individual vectors, you can manipulate them the same way you can a vector.
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Vectors in the Plane
- Vectors are needed in order to describe a plane and can give the direction of all dimensions in one vector equation.
- The plane determined by this point and vector consists of those points , with position vector , such that the vector drawn from to is perpendicular to .
- Recall that two vectors are perpendicular if and only if their dot product is zero.
- The vectors and can be visualized as vectors starting at and pointing in different directions along the plane.
- Calculate the directions of the normal vector and the directional vector of a reference point
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Vector-Valued Functions
- A vector function covers a set of multidimensional vectors at the intersection of the domains of , , and .
- Also called vector functions, vector valued functions allow you to express the position of a point in multiple dimensions within a single function.
- The input into a vector valued function can be a vector or a scalar.
- In Cartesian form with standard unit vectors (i,j,k), a vector valued function can be represented in either of the following ways:
- This is a three dimensional vector valued function.
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Vector Fields
- A vector field is an assignment of a vector to each point in a subset of Euclidean space.
- In vector calculus, a vector field is an assignment of a vector to each point in a subset of Euclidean space.
- The elements of differential and integral calculus extend to vector fields in a natural way.
- A vector field for the movement of air on Earth will associate for every point on the surface of the Earth a vector with the wind speed and direction for that point.
- A gravitational field generated by any massive object is a vector field.
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Conservative Vector Fields
- A conservative vector field is a vector field which is the gradient of a function, known in this context as a scalar potential.
- A conservative vector field is a vector field which is the gradient of a function, known in this context as a scalar potential.
- Therefore, the curl of a conservative vector field is always .
- A vector field , whose curl is zero, is called irrotational .
- Such vortex-free regions are examples of irrotational vector fields.
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Surface Integrals of Vector Fields
- Consider a vector field on ; that is, for each in , is a vector.
- The surface integral of vector fields can be defined component-wise according to the definition of the surface integral of a scalar field; the result is a vector.
- Alternatively, if we integrate the normal component of the vector field, the result is a scalar.
- where is the position vector and is a unit vector in radial direction.
- Explain relationship between surface integral of vector fields and surface integral of a scalar field
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Equations of Lines and Planes
- A line is a vector which connects two points on a plane and the direction and magnitude of a line determine the plane on which it lies.
- The position vector of point is called and the position vector of point is called .
- The vector from to is called vector .
- Vectors and are parallel to each other.
- where represents the location of vector on plane .