f : 1, 2, 3 → a, b, c, d is f = (1, a), (2, c), (3, d). Which of these describes f?

Relations & Functions · Question 84 of 125

Question 84

MediumOriginal question

$f : \{1, 2, 3\} \to \{a, b, c, d\}$ is $f = \{(1, a), (2, c), (3, d)\}$ . Which of these describes $f$ ?

One-one and ontoCorrect answerYour answerNeither one-one nor ontoCorrect answerYour answerOnto but not one-oneCorrect answerYour answerOne-one but not ontoCorrect answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer D

Correct answer: D

No two elements share an image: one-one.
b is no element's image: not onto.

Concept: A function on a finite set
Typical timeTypical: 90 s
Your timeYours: —

The rule this testsOne-one functions

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f:{1,2,3}→{a,b,c,d}f : \{1, 2, 3\} \to \{a, b, c, d\}f:{1,2,3}→{a,b,c,d} is f={(1,a),(2,c),(3,d)}f = \{(1, a), (2, c), (3, d)\}f={(1,a),(2,c),(3,d)}. Which of these describes fff?

Explanation

$f : \{1, 2, 3\} \to \{a, b, c, d\}$ is $f = \{(1, a), (2, c), (3, d)\}$ . Which of these describes $f$ ?