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OpenStudy (rock_mit182):
Evaluate following two compositions:
a: (f ° g) (x)
b: (h° g) (x)
f(x) = 2x+5;
g(x) = x^2-3;
h(x) = (7-x)/(3)
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OpenStudy (rock_mit182):
f ((7-x)/(3) ) by definition
(f°h)(x) = ((7-x)/(3) )^2 -3
OpenStudy (rock_mit182):
\[(f ° h)(x) = (\frac{ 7-x }{ 3 } )^{2}-3\]
OpenStudy (rock_mit182):
h (g(x)) by definition
h (x^2-3)
OpenStudy (rock_mit182):
\[(h ° g)(x) = \frac{ 7-x ^{2}-3 }{ 3} \]
OpenStudy (rock_mit182):
(-x^2+4)/(3)
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OpenStudy (rock_mit182):
@iPwnBunnies
OpenStudy (aum):
a: (f ° g) (x) = f( g(x) )
f(x) = 2x+5; g(x) = x^2-3.
f( g(x) ) = 2(x^2-3) + 5 = 2x^2 - 6 + 5 = 2x^2 - 1
OpenStudy (rock_mit182):
A = (f ° g)(x) = f(g(x)) by definition
\[f(x ^{2}-3)\]
\[2(x ^{2}-3) +5\]
OpenStudy (rock_mit182):
\[(f ° g)(x) = 2x ^ {2} -6 +5 -->2x ^{2}-1\]
OpenStudy (aum):
correct. Do the next one the same way. b: (h° g) (x)
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OpenStudy (aum):
b: (h° g) (x) = h( g(x) )
g(x) = x^2-3; h(x) = (7-x)/(3)
(h° g) (x) = h( g(x) ) = h( x^2-3 ) = ( 7 - (x^2-3) ) / 3 = (7 - x^2 + 3) / 3 = (10-x^2)/3
OpenStudy (rock_mit182):
b: (h°g)(x) = h(g(x)) by definition
h(x^2-3)
\[\frac{ 7-(x ^{2}-3) }{ 3 } = \frac{ 10-x ^{2} }{ 3 }\]
OpenStudy (aum):
correct.
OpenStudy (rock_mit182):
THanks a lot, you have been helpfull
OpenStudy (aum):
you are welcome.
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OpenStudy (rock_mit182):
\[h(x ^{2}-3)\]
OpenStudy (rock_mit182):
\[f ^{-1}(x) = 2y +5\]
OpenStudy (rock_mit182):
x= 2y + 5
-5 +x = 2y
OpenStudy (rock_mit182):
\[-\frac{ 5 }{ 2 }+\frac{ x }{ 2 } = y\]
OpenStudy (rock_mit182):
\[f ^{-1}(x) = \frac{ x }{ 2 }- \frac{ 5 }{ 2 }\]
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OpenStudy (rock_mit182):
\[h ^{-1}(x) =\]
OpenStudy (rock_mit182):
\[x = \frac{ 7-y }{ 3 }\]
OpenStudy (rock_mit182):
\[3x=7-y\]
OpenStudy (rock_mit182):
\[3x-7=-y\]
OpenStudy (rock_mit182):
\[-3x+7 = y\]
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OpenStudy (rock_mit182):
\[h ^{-1}(x) = -3x+7\]
OpenStudy (rock_mit182):
\[(2x+5)- (\frac{ 7-x }{ 3 }) = 2x+5 -\frac{ 7 }{ 3 }+\frac{ x }{3 }\]