Domain of two functions

[kristinelizabeth23]

Ok so the problem says:
Let F(X) and G(X) be functions with domain ((F(X))=[0,10] and Domain ((G(X))=(3,infinity) Find and simplify the domain of (FG)(X). (give answer in intercal notation.)

ok, so this is what I did... I looked at the two domains and saw that from 0-10 and 3-infinity...that the domain of the two together would be: (3,10]
can you please tell me if that is right or not? and If I'm wrong can you tell me what I need to do?

 

[tkhunny]

Please explain what is meant by the fairly ambiguous notation (FG)(x).

1) F(G(x))?
2) F(x)*G(x)?
3) Other?

 

[JeffM]

Ok so the problem says:
Let F(X) and G(X) be functions with domain ((F(X))=[0,10] and Domain ((G(X))=(3,infinity) Find and simplify the domain of (FG)(X). (give answer in intercal notation.)

ok, so this is what I did... I looked at the two domains and saw that from 0-10 and 3-infinity...that the domain of the two together would be: (3,10]
can you please tell me if that is right or not? and If I'm wrong can you tell me what I need to do?

As tkhunny says, what is the function the domain of which you are to find: is it F(G(x)) or [F(x) * G(x)]? It is imposible to tell you whether you are right or not without being sure of the question. The answers are VERY different. In fact if you are able to give correct answers to both cases, I suspect you will do just fine on this topic.

 

[kristinelizabeth23]

Thanks for helping, but that's exactly how the teacher wrote it. so I have no clue what he is wanting. haha. Maybe it was a typo? Because I do not understand where the teacher is coming from. :/

Please explain what is meant by the fairly ambiguous notation (FG)(x).

1) F(G(x))?
2) F(x)*G(x)?
3) Other?

 

[tkhunny]

Well, it is hoped that notation would be explained.

I suppose it is 2) F(x)*G(x), since the other doesn't work well. We don't know the Range of G(x)!

Having said that, I have to agree with your original response. :wink: