The relation f is defined by f (x) = {X2 , 0<X<3 / 3x 2 < X < 10

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asked Feb 7, 2018 in Mathematics by Rohit Singh (61,782 points) 35 133 354

The relation f is defined by f (x) = {X2 , 0<X<3 / 3x 2 < X < 10

The relation g is defined by g(x) = { X2 , 0<X<2 / 3x, 2<X< 10

Show that f is a function and g is not a function.

1 Answer

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answered Feb 7, 2018 by sameer (82,980 points) 5 11 37

The relation f is defined as

It is observed that for
0 ≤ x < 3, f(x) = x2
3 < x ≤ 10, f(x) = 3x
Also, at x = 3, f(x) = 32 = 9 or f(x) = 3 × 3 = 9 i.e., at x = 3, f(x) = 9
Therefore, for 0 ≤ x ≤ 10, the images of f(x) are unique. Thus, the given relation is a function.
The relation g is defined as

It can be observed that for x = 2, g(x) = 22 = 4 and g(x) = 3 × 2 = 6

Hence, element 2 of the domain of the relation g corresponds to two different images i.e., 4 and 6.
Hence, this relation is not a function.

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