The relation is defined by
The relation is defined by
Show that is a function and is not a function.
To determine whether the given relations are functions, we need to check if each element in the domain has exactly one image.
For relation f:
The relation f is defined by
The domain of f is . We need to verify that at the point where both definitions overlap (), the values are equal.
At :
- From first definition:
- From second definition:
Since both definitions give the same value at , every element in the domain has exactly one image. Therefore, f is a function.
For relation g:
The relation g is defined by
The domain of g is . We need to check the point where both definitions overlap ().
At :
- From first definition:
- From second definition:
Since both definitions give different values at , the element 2 has two images (4 and 6). This violates the definition of a function. Therefore, g is not a function.
Explanation
The question tests understanding of the definition of a function. A relation is a function if and only if each element in the domain has exactly one unique image. For piecewise-defined relations, we must check the boundary points where two definitions overlap. If both definitions give the same value at the boundary, the relation is a function. If they give different values, the relation is not a function because one element would have two images.
Solution Steps
Step 1: Identify the domain of f as and check the overlap point
Step 2: Calculate from both definitions: both give , so f is a function
Step 3: Identify the domain of g as and check the overlap point
Step 4: Calculate from both definitions: one gives , the other gives
Step 5: Conclude that g is not a function since has two different images