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Hi I have another question like this that I can’t figure out :)

Hi I have another question like this that I can’t figure out :)-example-1
User Randers
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1 Answer

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Answer:

f(g(-1)) = -8 and g(f(1/2) = 4/19.

Explanation:

The question specifies f(x) = x^2 + 9x and g(x) = 1/x. The question requires that there should be composite functions. This means a function in a function. Therefore, f(g(x)) means that the function g(x) is taken is an input in the function f(x). Simply replace g(x) instead of x in f(x). This gives:

f(g(x)) = (1/x)^2 + 9(1/x) = x^(-2) + 9/x.

Similar process for g(f(x)) gives:

g(f(x)) = 1/(x^2 + 9x).

Now there are two separate composite functions. Now taking inputs in the composite functions:

f(g(-1)) = (-1)^(-2) + 9/(-1) = 1 - 9 = -8.

g(f(0.5) = 1/(0.5^2 + 9(0.5)) = 1/(0.25+4.5) = 1/4.75 = 100/475 = 4/19.

Therefore f(g(-1)) = -8 and g(f(1/2) = 4/19!!!

User Adeem
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