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# Maths C3 - Distinguishing between Functions...help? Watch

1. Can someone explain the answer to this question? Why is f(x) a function but g(x) isn't??
This question is taken from the Edexcel C3 Modular Maths Textbook (Exercise 2C Q3)
2. (Original post by Philip-flop)
Can someone explain the answer to this question? Why is f(x) a function but g(x) isn't??
This question is taken from the Edexcel C3 Modular Maths Textbook (Exercise 2C Q3)
To be a function every input must produce exactly one output. For g(x) an input of 4 would produce no output, so it isn't a function.

If g(x) had its domain restricted by writing next to it it would be a function because now all allowed inputs do produce an output.
3. (Original post by sindyscape62)
To be a function every input must produce exactly one output. For g(x) an input of 4 would produce no output, so it isn't a function.

If g(x) had its domain restricted by writing next to it it would be a function because now all allowed inputs do produce an output.
Omg. Thank you for an amazing explanation!! It makes sense now. I was being so daft!! :P

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