An equation is a mathematical representation that defines the relationship that exists between natural or human variables. Such variables can be dependent or independent. Some mathematical relationships were discovered many years ago, and their contribution to human life is indispensable. Many of these equations are still applied in your day to day life.

**The Pythagorean Theorem.**

The equation is stated as the square of the hypotenuse of a triangle is equal to the sum of squares of both the base and the height. It is attributed to Pythagoras, and it is applied in modern triangulation, surveying and GPS navigation.

**The logarithm and related identities.**

Its explanation is that you can multiply numbers by adding related variables. In an attempt to make multiplication of large numbers simpler, Scottish Laird John Napier made an effort and discovered this mathematical relationship. The relationship is still applied in understanding radioactive decay.

**Calculus theorem.**

This is a mathematical identity that allows calculation of an instantaneous rate of change. It was defined by Isaac Newton and Gottfried Leibniz in the 17th century. It is widely used by scientists and in any mathematical problem where an optimal solution is needed. Currently, it is used in medicine, engineering, economics and computer-related studies.

**Law of Gravitation.**

This is a definition of gravitational forces between two objects. The definition was brought up by Isaac Newton, who plagiarized the work of Robert Hooke and possibly applied some concepts from Johannes Kepler. It is majorly employed during space missions to locate optimal gravitational tubes that are energy efficient.

**Analysis of complex numbers.**

The equation states that the square root of a negative number is an imaginary number. The concept of imaginary numbers and the related analysis was brought up by Girolamo Cardano. The idea was later advanced by John Wallis and Raphael Bombelli. It is applied in complex mathematics and electrical engineering.

**Euler’s formula of polyhedral.**

The concept defines a structure or space’s shape irrespective of alignment. Descartes explained the relationship and later proved by Leonhard Euler. The equation is central to the development of topography and understanding the behavior of the DNA.

**Schrodinger’s equation.**

This is a concept that is applied in chemistry and defines matter as a wave rather than a particle. The equation described the dual nature of matter and was first discovered by Louis-Victor de Broglie. Erwin Schrodinger then derived it. It is very helpful in understanding semiconductors and transistors that are used in computer technology.

Mathematical relationships between various variables are helpful in defining complex concepts. Even though the world continues to evolve, ancient equations are still very useful in different disciplines. Their contribution to human life is invaluable. They make computations simpler and easier.