Question

Consider these functions from the set of students in a discrete mathematics class. Under what conditions is the function one-to-one if it assigns to a student his or her

1. Mobile phone number
2. Student identification number
3. Final grade in the class
4. Home town.

Short answer

1. It one-to-one assigns to a student his or her mobile phone number if and only if no students share the same mobile number.
2. It one-to-one assigns to a student his or her student identification number is only and only if no students share the same identification number
3. It one-to-one assigns if and only if each and every student in the class has got different final grades than other classmates.
4. It one-to-one assigns if and only if each and every student in the class is coming from different home towns.

Step-by-step solution

Step: 1

1. It one-to-one assigns to a student his or her mobile phone number if and only if no students share the same mobile number.
2. It one-to-one assigns to a student his or her student identification number is only and only if no students share the same identification number
3. It one-to-one assigns if and only if each and every student in the class has got different final grades than other classmates.
4. It one-to-one assigns if and only if each and every student in the class is coming from different home towns.