Let's go through each question one by one from the image and solve them accordingly:
1. Given functions f(x)=2x+2 and g(x)=x2−3:
a) Find (f∘g)(x) (composition of f and g):
(f∘g)(x) means f(g(x)).
f(g(x))=f(x2−3)=2(x2−3)+2=2x2−6+2=2x2−4
So, (f∘g)(x)=2x2−4.
b) Find (g∘f)(x) (composition of g and f):
(g∘f)(x) means g(f(x)).
g(f(x))=g(2x+2)=(2x+2)2−3=(4x2+8x+4)−3=4x2+8x+1
So, (g∘f)(x)=4x2+8x+1.
2. Explain why (f∘g)(x) is not always the same as (g∘f)(x), and give an example:
The composition of functions depends on the order of operations. When composing f and g, the operations performed on x are different. For example, in (f∘g)(x), the function g(x) is applied first, followed by f, while in (g∘f)(x), f(x) is applied first.
Example:
From question 1, we have:
(f∘g)(x)=2x2−4
(g∘f)(x)=4x2+8x+1
Clearly, 2x2−4=4x2+8x+1, so the two compositions are not the same.
3. Given f(x)=2x+3 and g(x)=x−1, find (f∘g)−1(x) (the inverse of the composition of f and g):
First, find (f∘g)(x):
(f∘g)(x)=f(g(x))=f(x−1)=2(x−1)+3=2x−2+3=2x+1
Now, find the inverse of f∘g:
Set y=2x+1, and solve for x:
y=2x+1y−1=2xx=2y−1
Thus, the inverse is:
(f∘g)−1(x)=2x−1
4. If f(x)=3x−2 and (f∘g)(x)=6x+1, find g(x):
Start by expressing (f∘g)(x):
(f∘g)(x)=f(g(x))=3g(x)−2
Given that (f∘g)(x)=6x+1, we have:
3g(x)−2=6x+1
Solve for g(x):
3g(x)=6x+1+2=6x+3g(x)=36x+3=2x+1
So, g(x)=2x+1.
5. From problem 1, find:
a) (f∘g)(2):
Recall from problem 1 that (f∘g)(x)=2x2−4.
Now, substitute x=2:
(f∘g)(2)=2(22)−4=2(4)−4=8−4=4
b) (g∘f)(−2):
Recall from problem 1 that (g∘f)(x)=4x2+8x+1.
Now, substitute x=−2:
(g∘f)(−2)=4(−2)2+8(−2)+1=4(4)−16+1=16−16+1=1
Let me know if you need further details or explanations!
Related Questions:
Can you explain the step-by-step process of finding the inverse of a composition of functions?
What are the main conditions for two functions to be inverse to each other?
How does the domain of a composite function differ from that of individual functions?
What are some real-life applications of function compositions?
Can you provide an example where the composition of two functions results in a constant function?
Tip:
When finding the composition of two functions, always apply the second function first and then the first function to avoid errors.
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Math Problem Analysis
Mathematical Concepts
Function composition Inverse functions Quadratic functions Algebra