Division by zero: why not?
A strict ban on division by zero is imposed even in the junior classes of the school. Children usually do not think about its causes, but in fact to know why something is forbidden, and interesting, and useful.
Arithmetic operations, which are studied inschool, are unequal in terms of mathematicians. They recognize as full only two of these operations - addition and multiplication. They enter into the very concept of a number, and all other actions with numbers somehow are built on these two. That is, it is impossible not only to divide by zero, but also division in general.
Subtraction and division
What does the rest of the action lack? Again, from school it is known that, for example, subtract from seven four means to take seven sweets, four of them to eat and count those that will remain. But mathematicians do not solve the problem of eating sweets and generally perceive them completely differently. For them, there is only addition, that is, record 7 - 4 means a number that, in the sum with the number 4, will be 7. That is, for mathematicians 7 - 4 - this is a short entry of the equation: x + 4 = 7. This is not a subtraction, but a task - find a number that must be put in place of x.
The same applies to division and multiplication. Dividing ten by two, the junior student places ten candies into two identical heaps. The mathematician also here sees the equation: 2 · x = 10.
And it turns out why the division intozero: it is simply impossible. The 6: 0 record should be transformed into the equation 0 · x = 6. That is, it is required to find a number that can be multiplied by zero and get 6. But it is known that zero multiplication always gives zero. This is an essential property of zero.
Thus, there is no such number, which,multiplying by zero, would give a number different from zero. Hence, this equation has no solution, there is no such number that would correspond to the 6: 0 record, that is, it does not make sense. Its meaninglessness is also said when the division by zero is forbidden.
Is zero divided by zero?
Is it possible to divide zero by zero? The equation 0 · x = 0 does not cause difficulties, and we can take this zero for x and obtain 0 · 0 = 0. Then 0: 0 = 0? But if, for example, we take 0 as 1, we also get 0 · 1 = 0. We can take any number as x and divide by zero, and the result will remain the same: 0: 0 = 9, 0: 0 = 51 and so Further.
Thus, you can insert in this equationabsolutely any number, and it is impossible to choose any particular, it is impossible to determine what number is indicated by the record 0: 0. That is, this record also does not make sense, and division by zero is still impossible: it does not even divide by itself.
This is an important feature of the operation of division, that is, multiplication and the number associated with it, zero.
The question remains: why you can not divide by zero, but can you subtract it? It can be said that real mathematics begins with this interesting question. To find the answer to it, you need to learn the formal mathematical definitions of numerical sets and get acquainted with the operations on them. For example, there are not only simple, but also complex numbers, divisionwhich differs from the division of ordinary. This is not part of the school curriculum, but university lectures on mathematics begin with this.