Horizontal eccentricity

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Horizontal eccentricity refers to the horizontal axis, measured in degrees, along the visual field. The blind spot extends from an eccentricity d1 to eccentricity d2 in temporal direction from the fovea. The size of the blind spot can be calculated as

Temple (anatomy) side of the head behind the eyes

The temple indicates the side of the head behind the eye between the forehead and the ear. The bone beneath is the temporal bone as well as part of the sphenoid bone.

Fovea centralis

The fovea centralis is a small, central pit composed of closely packed cones in the eye. It is located in the center of the macula lutea of the retina.

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Slope In mathematics, the slope or gradient of a line describes its steepness, incline, or grade; number that describes both the direction and the steepness of the line

In mathematics, the slope or gradient of a line is a number that describes both the direction and the steepness of the line. Slope is often denoted by the letter m; there is no clear answer to the question why the letter m is used for slope, but it might be from the "m for multiple" in the equation of a straight line "y = mx + b" or "y = mx + c".

Angle of view angular extent of a given scene that is imaged by a camera

In photography, angle of view (AOV) describes the angular extent of a given scene that is imaged by a camera. It is used interchangeably with the more general term field of view.

Angular aperture

The angular aperture of a lens is the angular size of the lens aperture as seen from the focal point:

Gudermannian function function that relates the circular functions and hyperbolic functions without using complex numbers

The Gudermannian function, named after Christoph Gudermann (1798–1852), relates the circular functions and hyperbolic functions without explicitly using complex numbers.

Inverse trigonometric functions inverse function of the trigonometric function

In mathematics, the inverse trigonometric functions are the inverse functions of the trigonometric functions. Specifically, they are the inverses of the sine, cosine, tangent, cotangent, secant, and cosecant functions, and are used to obtain an angle from any of the angle's trigonometric ratios. Inverse trigonometric functions are widely used in engineering, navigation, physics, and geometry.

Trigonometric substitution

In mathematics, trigonometric substitution is the substitution of trigonometric functions for other expressions. One may use the trigonometric identities to simplify certain integrals containing radical expressions:

Substitution 1. If the integrand contains a2 − x2, let

and use the identity

Substitution 2. If the integrand contains a2 + x2, let

and use the identity

Substitution 3. If the integrand contains x2 − a2, let

and use the identity

Great-circle distance shortest distance between two points along the surface of a sphere

The great-circle distance or orthodromic distance is the shortest distance between two points on the surface of a sphere, measured along the surface of the sphere. The distance between two points in Euclidean space is the length of a straight line between them, but on the sphere there are no straight lines. In spaces with curvature, straight lines are replaced by geodesics. Geodesics on the sphere are circles on the sphere whose centers coincide with the center of the sphere, and are called great circles.

In mathematics, a quadratic integral is an integral of the form

In mathematics, there are several integrals known as the Dirichlet integral, after the German mathematician Peter Gustav Lejeune Dirichlet.

Hyperbolic secant distribution

In probability theory and statistics, the hyperbolic secant distribution is a continuous probability distribution whose probability density function and characteristic function are proportional to the hyperbolic secant function. The hyperbolic secant function is equivalent to the reciprocal hyperbolic cosine, and thus this distribution is also called the inverse-cosh distribution.

Conical coordinates

Conical coordinates are a three-dimensional orthogonal coordinate system consisting of concentric spheres and by two families of perpendicular cones, aligned along the z- and x-axes, respectively.

The n-vector representation is a three-parameter non-singular representation well-suited for replacing latitude and longitude as horizontal position representation in mathematical calculations and computer algorithms.

Hammer projection map projection

The Hammer projection is an equal-area map projection described by Ernst Hammer in 1892. Using the same 2:1 elliptical outer shape as the Mollweide projection, Hammer intended to reduce distortion in the regions of the outer meridians, where it is extreme in the Mollweide.

This is a summary of differentiation rules, that is, rules for computing the derivative of a function in calculus.

Argument (complex analysis) math function

In mathematics, the argument is a multi-valued function operating on the nonzero complex numbers. With complex number z visualized as a point in the complex plane, the argument of z is the angle between the positive real axis and the line joining the point to the origin, shown as φ in figure 1 and denoted arg z. To define a single-valued function, the principal value of the argument is used. It is chosen to be the unique value of the argument that lies within the interval (–π, π].

Gall stereographic projection Cylindrical map projection

The Gall stereographic projection, presented by James Gall in 1855, is a cylindrical projection. It is neither equal-area nor conformal but instead tries to balance the distortion inherent in any projection.