Given two vectors, a and b, their dot product, represented as a ● b, is equal to their magnitudes multiplied by the cosine of the angle between them, θ, and is a scalar value.
a ● b = ║a║║b║cos(θ)
Cross Product:Given two vectors, a and b, their cross product, which is a vector, is represented as a X b and is equal to their magnitudes multiplied by the sine of the angle between them, θ, and then multiplied by a unit vector, n, which points perpendicularly away, via the right-hand rule, from the plane that a and b define.
a X b = ║a║║b║sin(θ)n
A dot is a point. There is no point between the dot. There could be a point between two dots, but that is not what you asked. And if there was a point between two dots, it would just be another dot.
Unit vectors are perpendicular. Their dot product is zero. That means that no unit vector has any component that is parallel to another unit vector.
That fact alone doesn't tell you much about the original two vectors. It only says that (magnitude of vector-#1) times (magnitude of vector-#2) times (cosine of the angle between them) = 1. You still don't know the magnitude of either vector, or the angle between them.
in 2 and 3 dimensions they turn out to be pretty much the same, but what would perpendicular mean in 4 or 6 dimensions? For example a line perpendicular to another intersects it and creates a 90 degree angle, it is also normal and a line can be normal to a plane also. Normal is a more general term that can be used in higher dimensions and other setting where perpendicular might make no sense. For example, if you know what a dot product is that two vectors are normal if their dot product is zero, These may be n dimensional vectors and perpendicular would make no sense. In many more abstract settings normal works but perpendicular would have no meaning at all. There are more technical explanations but I hope to make this answer more intuitive! There is a very slight difference between NORMAL and PERPENDICULAR. Well NORMAL is that perpendicular which is drawn at the contact point between two meeting lines. Its simple as this. For example in case of tangents (which is drawn to find the direction of a point in a curve) the perpendicular draw at the meeting point of the tangent and the curve is called normal. Its like, every normal is a perpendicular but all perpendiculars are not normal. I hope this clears all your doubt.
Line or reflective symmetry is really a special case of rotational symmetry but from a different viewpoint. In line symmetry imagine a line going north to south on the page. If you rotate an image out of the page around that line through 180 degrees you get a reflection. For rotational symmetry imagine that same line being perpendicular to the page so that you see it as a dot. The image is then rotated around that dot.
cross: torque dot: work
Dot Product:Given two vectors, a and b, their dot product, represented as a ● b, is equal to their magnitudes multiplied by the cosine of the angle between them, θ, and is a scalar value.a ● b = ║a║║b║cos(θ)Cross Product:Given two vectors, a and b, their cross product, which is a vector, is represented as a X b and is equal to their magnitudes multiplied by the sine of the angle between them, θ, and then multiplied by a unit vector, n, which points perpendicularly away, via the right-hand rule, from the plane that a and bdefine.a X b= ║a║║b║sin(θ)n
Because in dot product we take projection fashion and that is why we used cos and similar in cross product we used sin
A dot product is a scalar product so it is a single number with only one component. A cross product or vector product is a vector which has three components like the original vectors.
Dot product and cross product are used in many cases in physics. Here are some examples:Work is sometimes defined as force times distance. However, if the force is not applied in the direction of the movement, the dot product should be used. Note that here - as well as in other cases where the dot product is used - the product is greatest when the angle is zero; also, the result is a scalar, not a vector.The cross product is used to define torque (distance from the axis of rotation, times force). In this case, the product is greatest when the two vectors are at right angles. Also - as in any cross product - the result is also a vector.Several interactions between electricity and magnetism are defined as cross products.
The dot-product and cross-product are used in high order physics and math when dealing with matrices or, for example, the properties of an electron (spin, orbit, etc.).
They give us different results. The dot product produces a number, while the scalar multiplication produces a vector.
Yes and no. It's the dot product, but not the cross product.
(A1) The dot product of two vectors is a scalar and the cross product is a vector? ================================== (A2) The cross product of two vectors, A and B, would be [a*b*sin(alpha)]C, where a = |A|; b = |B|; c = |C|; and C is vector that is orthogonal to A and B and oriented according to the right-hand rule (see the related link). The dot product of the two vectors, A and B, would be [a*b*cos(alpha)]. For [a*b*sin(alpha)]C to equal to [a*b*cos(alpha)], we have to have a trivial solution -- alpha = 0 and either a or b be zero, so that both expressions are zeroes but equal. ================================== Of course one is the number zero( scalar), and one is the zero vector. It is a small difference but worth mentioning. That is is to say if a or b is the zero vector, then a dot b must equal zero as a scalar. And similarly the cross product of any vector and the zero vector is the zero vector. (A3) The magnitude of the dot product is equal to the magnitude of the cross product when the angle between the vectors is 45 degrees.
Cross product tests for parallelism and Dot product tests for perpendicularity. Cross and Dot products are used in applications involving angles between vectors. For example given two vectors A and B; The parallel product is AxB= |AB|sin(AB). If AXB=|AB|sin(AB)=0 then Angle (AB) is an even multiple of 90 degrees. This is considered a parallel condition. Cross product tests for parallelism. The perpendicular product is A.B= -|AB|cos(AB) If A.B = -|AB|cos(AB) = 0 then Angle (AB) is an odd multiple of 90 degrees. This is considered a perpendicular condition. Dot product tests for perpendicular.
The dot-product of two vectors is the product of their magnitudes multiplied by the cosine of the angle between them. The dot-product is a scalar quantity.
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