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# C3 finding the range watch

1. are my ranges for g(x) right ? One of them doesn't match the answer thanks

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2. (Original post by coconut64)
are my ranges for g(x) right ? One of them doesn't match the answer thanks

Attachment 608266608264
The first range is right.
3. (Original post by solC)
The first range is right.
g(x)<-7 is unnecessary since -7<8 anyway
So-7 is also right ? Thanks
4. (Original post by coconut64)
So-7 is also right ? Thanks
In fact, that second one is wrong because, even with the first range, g(x)<-7 doesn't make sense because there are clearly values between -7 and 8 as seen from the graph.
Ignore what I first said, sorry.
5. (Original post by solC)
In fact, that second one is wrong because, even with the first range, g(x)<-7 doesn't make sense because there are clearly values between -7 and 8 as seen from the graph.
Ignore what I first said, sorry.
The second equation -x^2+3 has a domain of x>3 , so surely the range has to be less than -7
6. (Original post by coconut64)
are my ranges for g(x) right ? One of them doesn't match the answer thanks

EDIT : Wrong, ignore.
7. (Original post by solC)
In fact, that second one is wrong because, even with the first range, g(x)<-7 doesn't make sense because there are clearly values between -7 and 8 as seen from the graph.
Ignore what I first said, sorry.
Are you looking at the correct graph?

You should be looking at the graph of restricted to .

Coconut64 has drawn it correctly.

EDIT: Wrong, ignore.
8. (Original post by notnek)
Are you looking at the correct graph?

You should be looking at the graph of restricted to .

Coconut64 has drawn it correctly.

The answer given was g(x)<=8, so I assumed that they treated the whole thing as a single function.
9. (Original post by coconut64)
are my ranges for g(x) right ? One of them doesn't match the answer thanks
I just noticed you posted the answers in your OP. Can you also post a picture of the actual question i,e, a photograph of the textbook?
10. (Original post by notnek)
I just noticed you posted the answers in your OP. Can you also post a picture of the actual question i,e, a photograph of the textbook?
11. (Original post by coconut64)
are my ranges for g(x) right ? One of them doesn't match the answer thanks
Ignore what I've said so far. I just looked at your question again and noticed that g(x) is a single function. This is not two separate functions.

Did you realise that?
12. (Original post by solC)
The answer given was g(x)<=8, so I assumed that they treated the whole thing as a single function.
It is a single function - I read the question incorrectly.

So you're correct, sorry
13. (Original post by notnek)
It is a single function - I read the question incorrectly.

So you're correct, sorry
So if the questions are laid out like this gx then 2 equations , there is only one function so only one range should be given? But there are 2 domains though...
14. (Original post by coconut64)
So if the questions are laid out like this gx then 2 equations , there is only one function so only one range should be given? But there are 2 domains though...
The function is equal to for and equal to for .

So the domain of the function is actually all real numbers. It's just defined differently over different parts of the domain but it's a single function.

The range of the function is the set of values that f can be over the full domain. So in your graph, it's anything that y can be.

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