Finding the domain of a composite function

In summary, the conversation was about finding the domain of the composite function f(g(x)) where f(x)=sinx and g(x)=1-√x. The person was struggling with finding the domain and asked for a step-by-step explanation. The expert clarified that the domain is the region of input variable over which the function is valid and suggested starting with an easy example.
  • #1
lindseyam
7
0

Homework Statement



I started out with f(x)=sinx and g(x)=1-√x. I found f(g(x)) which is sin(1-√x) and now my problem is how to find the domain. I've really been struggling with the domain part and just need this one done step by step so i have an idea of how to actually do it.

Homework Equations





The Attempt at a Solution

 
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  • #2
start with finding the domain of g(x) and f(x)
 
  • #3
lanedance said:
start with finding the domain of g(x) and f(x)

If I knew how to get the domain I would but I'm having trouble with the domain for both parts.
 
  • #4
ok so what's your definition of domain?

Unless it is defined otherwise, I would informally interpret it as the region of input variable over which the function is valid

lets start with an easy but relevant example, what is the valid domain of [\itex]\mathbb{R} [/itex], for the function [\itex]h(x) = \sqrt{x}[/itex]
 

1. What is a composite function?

A composite function is a function that is created by combining two or more functions. The output of one function is used as the input for another function, creating a new function.

2. How do you find the domain of a composite function?

To find the domain of a composite function, you need to first find the domain of each individual function in the composite. Then, you need to determine which inputs will satisfy all of the individual function's domains. These inputs will be the domain of the composite function.

3. Can the domain of a composite function be different from the domain of its individual functions?

Yes, the domain of a composite function can be different from the domain of its individual functions. This is because when combining functions, certain inputs may be restricted due to the combination of the individual functions' domains.

4. What are some common mistakes when finding the domain of a composite function?

Some common mistakes when finding the domain of a composite function include forgetting to consider all of the individual functions' domains, not accounting for restrictions that may occur when combining functions, and not simplifying the final domain expression.

5. Can a composite function have an empty domain?

Yes, a composite function can have an empty domain if the combination of the individual functions' domains results in no valid inputs. This can occur if there are restrictions or contradictions when combining the individual functions.

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