What is the definition of irrational number? How to express it on the number axis? What is irrationality?

What is the definition of irrational number? How to express it on the number axis? What is irrationality?

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The rational number a is equal to its reciprocal, the rational number b is equal to its opposite, then the 2013 power of a + the 2013 power of b is equal to () If the rational number a is equal to its reciprocal and the rational number b is equal to its opposite, then the 2013 power of a + the 2013 power of b is equal to ()

The rational number a is equal to its reciprocal, then a =1 or -1
If the rational number b is equal to its opposite number, then b =0
2013 Power of a +2013 power of b equals ±1