Possibly 5th Century BC
Probably the ancient Egyptians who discovered that the diagonal of a unit square was not a rational number. And then discovered other such numbers.
Pythagoras discovred it to find unknown sides in a right angled triangle
He got killed
yes * * * * * No. Rational and irrational numbers are two DISJOINT subsets of the real numbers. That is, no rational number is irrational and no irrational is rational.
Hippasus, However Pythagoras could not accept the existence of irrational numbers, because he believed that all numbers had perfect values. But he could not disprove Hippasus' "irrational numbers" and so Hippasus was thrown overboard and drowned.
Pythagoras is called the father of numbers because he discovered the Pythagoras theoram.
Little is really ''known'' about this. Stories abound and many conflict. The surest element of the tales is that root 2 was the first number proven irrational. The favourite for "whodunnit" was Hippasus. Many tales are told of his death by drowning. "Whodun'''that"''' has various answers with Pythagoras as the favourite pusher. Other stories have Pythagoras ordering Hippasus drowned for revealing the existence of irrational numbers, which Pythagoras thought should be kept secret.
No He discovered how to work out the hypotenuse
Pythogora
Possibly 5th Century BC
No. For example, 20.5 is irrational; indeed it was one of the first irrational numbers to be discovered.
The amicable numbers 2620 and 2924 were discovered by the ancient Greek mathematician Pythagoras. These numbers have a special relationship where the sum of the factors of one number equals the other, and vice versa.
Probably the ancient Egyptians who discovered that the diagonal of a unit square was not a rational number. And then discovered other such numbers.
They are irrational numbers!
They are numbers that are infinite
The history of this is confused. The first irrational number found was almost certainly root 2. The man who proved this was probably Hippasus.Hippasus died by drowning, and some stories say that Pythagoras drowned him for proving the existence of an irational number which he thought was impossible. Others say that Pythagoras ordered the drowning of Hippasus for revealing the existence of an irrational number which should be kept fron public knowledge.