SOLUTION: I do not understand what the symbol is that looks like a multiplication symbol but is open like a miniature o. I looked in my book and found that it means something like (f o g)(x

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Question 355823: I do not understand what the symbol is that looks like a multiplication symbol but is open like a miniature o. I looked in my book and found that it means something like (f o g)(x) = f(g(x)). Like here is an example problem...
(f o h)(x),if f(x)=2x, g(x)=3x, and h(x)=4
or (f o g)(4), let f(x)=3x-2 and g(x)=x^2+x
I know I am not really attempting to answer the question, but I don't understand it to try to answer. Please help me!! I have a math test tonight!!

Found 2 solutions by Alan3354, ewatrrr:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
I do not understand what the symbol is that looks like a multiplication symbol but is open like a miniature o. I looked in my book and found that it means something like (f o g)(x) = f(g(x)). Like here is an example problem...
(f o h)(x),if f(x)=2x, g(x)=3x, and h(x)=4
or (f o g)(4), let f(x)=3x-2 and g(x)=x^2+x
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It's what you stated.
(f o g) (x) = f(g(x))
Evaluate g(x), then use that value in f(x)
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(f o h)(x),if f(x)=2x, g(x)=3x, and h(x)=4
h(x) = 4
(f o h)(x) = f(4) = 8
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or (f o g)(4), let f(x)=3x-2 and g(x)=x^2+x
g(4) = 40
f(20) = 58

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
HI,
You are absolutely correct (f 0 g)(x) means for every x in the f(x) function, g(x) has been substituted for it.
.
f(x)=2x & h(x)= 4
.
(note put the '4' in place of the x in the f(x) function)
(f o h)(x)= 2(4) = 8
.
(f o g)(4), let f(x)=3x-2 and g(x)=x^2+x
.
substitute x^2+x for x in the (3x-2) expresion
(f o g)(4) = (3(x^2+x)-2
.
solve for x = 4
(f o g)(4) = 3*(20)-2 = 58