The notion of unknown , derived from the Latin word incognĭtus, refers to what results unknown . The term has different uses according to context .
For example: "The current level of the basketball player is unknown because he hasn't played for seven months", "The mystery ended: the president announced that he will run again as a candidate and will aspire to re-election", “The singer did not clear the mystery and still does not confirm whether or not he will return with his old band ”.
In the field of mathematics , it is called an unknown unknown quantity that must be specified in a problem or in an equation to achieve its resolution. It can be said, therefore, that a mystery is one of the elements that constitute a mathematical expression.
In a equation , the unknown is an unknown value that, when discovered, allows to verify equality. In a problem, there may be several unknowns, each expressed by a symbol that cannot be repeated.
The problems that are solved with the rule of three , to cite a case, they are based on the presence of an unknown and three values known. Among these elements there is a linearity relationship given by proportionality.
If we know that, in a restaurant fast food is sold a hamburger to 50 pesos , and we intend to buy three hamburgers , we can resort to the rule of three to know the total price that we will have to pay, discovering the value of the unknown:
If a hamburger costs 50 pesos, three hamburgers cost x pesos.
1 hamburger = 50 pesos
3 burgers = x pesos
(3 × 50) / 1 = x
150 = x
This means that the unknown has a value of 150 : three hamburgers cost 150 pesos .
This is also known by the name of simple three rule , to distinguish it from the composed , in which there is a greater number of magnitudes which are used to find out the value of the unknown. In addition, in the example of hamburgers we are facing a simple rule of three case direct , since all magnitudes increase or decrease in the same direction, with a direct proportionality.
We can explain this by thinking of each one of them: we have the price from a hamburger which is fifty pesos, and we want to find out the one of three burgers. Well, if we increase any of these three values, we will be forced to increase the other two in the same proportion : if we knew the price of four hamburgers, that is to say if we multiplied by four the previous data, then the two remaining quantities would be Two Hundred weights and twelve burgers.
The concept of incognito has been part of mathematics for centuries, always with the aim of modeling algebraic problems of polynomials, that is, of expressions formed by a finite amount of variables and products between constants and variables. As alien as the mathematical theory may seem to us in everyday life, it could not be more present: every day we make decisions related to amounts, with amounts of money, with the order of things in a system, etc., and for all that and much more we use this science automatically
This brings us to the seemingly negative nuance that the term receives unknown in everyday speech: although it can also serve to denote mystery in an attractive sense, it is usually used when this lack of knowledge causes us an inconvenience. In mathematics, it is thanks to this doubt that problems exist, and it is they who move forward knowledge, the very reasons for research and constant learning. If there were no things to solve, then everything would lose sense , since life would become static.