Help with Understanding Composite Functions

In summary, a composite function is when one function's output is used as another function's input. The notation for this is f(g(x)), where 'x' is the input to the first function, g, and the output of g is used as the input for the second function, f. This is different from multiplying functions.
  • #1
frozenbananas
8
0

Homework Statement



posted in title

Homework Equations



none

The Attempt at a Solution


f+g would be

(2x^2+1) + (x-1) = 2x^2 + x so the domain for f+g is all real numbers but i don't know how to find the one for the composite. i am still confused as to what a composite function is, please help me! thank you!
 
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  • #2


composition of f&g is nothing but f o g which is the same as fg or f(g(x)).

So take the entire g(x) and put it wherever you see 'x' in f.
 
  • #3


the composite is simply g then? or is it f(x) multiplied by g(x)?
 
  • #4


frozenbananas said:
the composite is simply g then? or is it f(x) multiplied by g(x)?

As rock.freak said, it is f(g(x)), not g(x). 'x' is the input to g and then the output g(x) becomes the input to f. It is different to multiplying.

As an example: If g(x)=x+x^2 and f(x)=2x, then the composition gf(x) = 2x + (2x)^2
 

FAQ: Help with Understanding Composite Functions

What is a composite function?

A composite function is a combination of two or more functions, where the output of one function becomes the input of the next function. It is denoted as f(g(x)), which means the function f is applied to g(x).

How do you evaluate a composite function?

To evaluate a composite function, you need to substitute the inner function's output as the input for the outer function. For example, if f(x) = x^2 and g(x) = 3x+1, then f(g(x)) = f(3x+1) = (3x+1)^2 = 9x^2 + 6x + 1.

What is the order of operations for composite functions?

The order of operations for composite functions is innermost to outermost. This means that you should evaluate the inner function first and then use the result as the input for the outer function.

Can you simplify a composite function?

Yes, you can simplify a composite function by using algebraic techniques such as factoring, distributing, and combining like terms. This can help make the function easier to evaluate and understand.

How are composite functions used in real life?

Composite functions are used in many real-life scenarios, especially in mathematical modeling. For example, in economics, the demand for a product can be modeled as a composite function of factors such as price, income, and advertising. In physics, the position of an object can be modeled as a composite function of time and velocity.

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