function question

May 2016
380
3
england
can someone help me with the following. I think it does not as f(.5) can be subbed into both parts of the function which makes no sense.

(iii) Does the following represent a function from R to R?


f(x) =
x^2 , x ≤ 1,
x + 2, x > 0.
justify your answer
 

Plato

MHF Helper
Aug 2006
22,475
8,643
can someone help me with the following. I think it does not as f(.5) can be subbed into both parts of the function which makes no sense.
(iii) Does the following represent a function from R to R?
f(x) =
x^2 , x ≤ 1,
x + 2, x > 0.
justify your answer
As you say $(0.5,0.25)~\&~(0.5,2.5)$ are both in the relation.
But a function cannot contain two pairs with the same first term.
 
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