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Given a finite set X, a function f : X → X is one-one (respectively onto) if and
only if f is onto (respectively one-one) This is the characteristic property of a
finite set This is not true for infinite set
Rationalised 2023-24
RELATIONS AND FUNCTIONS
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Historical Note
The concept of function has evolved over a long period of time starting from
R Descartes (1596-1650), who used the word ‘function’ in his manuscript
“Geometrie” in 1637 to mean some positive integral power xn of a variable x
while studying geometrical curves like hyperbola, parabola and ellipse