Page 24 - Mathematics Class - XI

DEMONSTRATION
Join paper pins of the left hand strip to the paper pins on the right hand strip by threads or yarns in different
ways as shown in Figs. (c) to (f).

1 A 1 A
2 2
3 B 3 B

Fig. (c) Fig. (d)

1 1
A A
2 2
3 B 3 B

Fig. (e) Fig. (f)

OBSERVATION

1. In Fig. (c), ordered pairs are (1, A), (1, B), (2, A), (2, B) and (3, B).

These ordered pairs constitute a relation but not a function.

2. In Fig. (d), ordered pairs are (1, A), (2, A) and (3, A).
These ordered pairs constitute a relation as well as constant function.

3. In Fig. (e), ordered pairs are (1, B), (2, B) and (3, B).

These ordered pairs constitute a relation as well as constant function.

4. In Fig. (f), ordered pairs are (2, A) and (3, B).
These ordered pairs do not represent a function but represent a relation.

CONCLUSION

This activity shows that every relation is not a function but every function is a relation.

APPLICATION
This activity can be used to demonstrate different types of functions.

Knowledge Booster
A function can be represented verbally, algebraically, numerically and graphically.

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