In physics, the field strength of a field is the magnitude (size) of its (vector) value. This means that the force exerted by the field on a given object is proportional to the field strength.
In differential geometry, the field strength is another name for the curvature form. For the electromagnetic field, the curvature form is an antisymmetric matrix whose elements are the electric field and magnetic field: the electromagnetic tensor.
In radio engineering, field strength is the strength of radio waves in a particular location.
Field (physics)
In physics, a field means that a physical quantity is assigned to every point in space (or, more generally, spacetime). A field is seen as extending throughout a large region of space so that it influences everything. The strength of a field usually varies over a region. Michael Faraday became the first to coin the term "field", in 1849.
For some fields, there is a number for each point in space. They are called "scalar fields". For more complicated fields, there are more than one number for each point in space. They are called "vector fields" or "tensor fields". For example, one can model a gravitational field by a vector field where a vector indicates the acceleration a mass would experience at each point in space. Other examples are temperature fields or air pressure fields, which are often illustrated on weather reports by isotherms and isobars by joining up the points of equal temperature or pressure respectively.
It is now believed that quantum mechanics should underlie all physical phenomena.
A field theory is a physical theory that describes how one or more physical fields interact with matter.
Gradient
In vector calculus, the gradient of a multivariate function measures how steep a curve is. On a graph of the function, it is the slope of the tangent of that curve. More generally, it is a vector that points in the direction in which the function grows the fastest. Its coordinates are partial derivatives of that function. The gradient of a function "f" is often written as formula_1 or formula_2.
Trigonometric function
In mathematics, the trigonometric functions are a set of functions which relate angles to the sides of a right triangle. There are many trigonometric functions, the 3 most common being sine, cosine, tangent, followed by cotangent, secant and cosecant. The last three are called reciprocal trigonometric functions, because they act as the reciprocals of other functions. Secant and cosecant are rarely used.
The trigonometric functions sometimes are also called circular functions. They are functions of an angle; they are important when studying triangles, among many other applications. Trigonometric functions are commonly defined as ratios of two sides of a right triangle containing the angle, and can equivalently be defined as the lengths of various line segments from a unit circle (a circle with radius of one).
In order to define the trigonometric functions for the angle "A", start with a right triangle that contains the angle "A":
We use the following names for the sides of the triangle:
All triangles are taken to exist in Euclidean geometry, so that the inside angles of each triangle sum to π radians (or 180°); therefore, for a right triangle, the two non-right angles are between zero and π/2 radians. Notice that strictly speaking, the following definitions only define the trigonometric functions for angles in this range. We extend them to the full set of real arguments by using the unit circle, or by requiring certain symmetries and that they be periodic functions.
1) The sine of an angle is the ratio of the length of the opposite side to the length of the hypotenuse. In our case
Note that since all those triangles are similar, this ratio does not depend on the particular right triangle that is chosen, as long as it contains the angle "A".
The set of zeroes of sine (that is, the values of formula_2 for which formula_3) is
2) The cosine of an angle is the ratio of the length of the adjacent side to the length of the hypotenuse. In our case
The set of zeroes of cosine is
3) The tangent of an angle is the ratio of the length of the opposite side to the length of the adjacent side. In our case
The set of zeroes of tangent is
This is the same set as that of the sine function, since
The remaining three functions are best defined using the above three functions.
4) The cosecant csc("A") is the multiplicative inverse of sin("A"); it is the ratio of the length of the hypotenuse to the length of the opposite side:
5) The secant sec("A") is the multiplicative inverse of cos("A"); it is the ratio of the length of the hypotenuse to the length of the adjacent side:
6) The cotangent cot("A") is the multiplicative inverse of tan("A"); it is the ratio of the length of the adjacent side to the length of the opposite side:
One can also define the trigonometric functions by using power series:
and define tangent, cotangent, secant and cosecant using identities, see below.
Some important identities:
The hyperbolic functions are like the trigonometric functions, in that they have very similar properties. Each of six trigonometric functions has a corresponding hyperbolic form. They are defined in terms of the exponential function, which is based on the constant "e".
Gradient (disambiguation)
Gradient could mean:
Archer
An archer is someone who practices archery (shooting with bows and arrows).
Archer can also mean:
Archery
Archery is the practice of using a bow to shoot arrows. Archery has historically been used in hunting and combat and has become a precision sport. A person practicing archery is called an "archer", and one who enjoys or is an expert at archery is sometimes called an toxophilite.
The earliest evidence of archery dates back more than 9,000 years. The bow probably was used in hunting first and later adopted as a tool of warfare. It was one of the earliest forms of artillery.
Classical civilizations, notably the Persians, Macedonians, Nubians, Greeks, Parthians, Indians, Japanese, Chinese, and Koreans, had large numbers of archers in their armies. Archers in chariots were especially important in armies of ancient Egypt. Arrows were very destructive against massed formations, and the use of archers helped win battles. The army of the Mongol Empire was mostly archers on horseback.
John Cena
John Felix Anthony Cena Jr. (born April 23, 1975) is an American professional wrestler, hip hop musician and actor. He currently works for the WWE. Cena has won the WWE Championship/WWE World Heavyweight Championship thirteen times, the World Heavyweight Championship thrice, the United States Championship five times and the World Tag Team Championship twice. Also, Cena won the Royal Rumble in 2008 and 2013. As for his musical career, Cena has released an album called "you cant see me". Cena has also been featured in the movies "The Marine", "12 Rounds" and "Legendary". He will star as Peacemaker in the 2022 movie "The Suicide Squad" and his own television series for HBO Max.
In Baseball, he is a Red Sox fan turned Rays fan.
Cena was signed by then Person in charge of Talent Relations, Jim Ross on behalf on WWF. According to Ross, when he returned to Connecticut after signing Cena he walked into Vince McMahon's office and told him "I just signed your main event for WrestleMania in 5 years." Cena would eventually make his WrestleMania debut 3 years later at WrestleMania XX winning the WWE United States Championship from The Big Show, and his Main event WrestleMania debut 4 years later winning the WWE Championship, from John "Bradshaw" Layfield.
During the match between Barrett and Orton, Orton won so Cena was forced to retire. He was rehired by Wade Barrett and defeated him at TLC: Tables, Ladders and Chairs Pay Per View.
He was drafted to SmackDown as the first pick in the 2011 WWE Draft, but before the end of the night, he was drafted back to Raw.