Mathematics
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OpenStudy (rosepetalingg):
Find the inverse of this function
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OpenStudy (rosepetalingg):
can someone explain how to do this?
OpenStudy (rosepetalingg):
@Lowkey.S @Loli @babygirl4556
OpenStudy (rosepetalingg):
@imqwerty @zepdrix @.Sam. @Awolflover1
OpenStudy (eliesaab):
You have to solve the equation
\[y=\sqrt[3]{x-2}+8
\]
for x in terms of y
OpenStudy (rosepetalingg):
okay so what would be my first step after that? do I get rid of the square root? I am really having trouble
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OpenStudy (rosepetalingg):
@eliesaab
OpenStudy (eliesaab):
\[y-8=\sqrt[3]{x-2}
\]
OpenStudy (eliesaab):
Cube both sides
OpenStudy (rosepetalingg):
\[y^3-8^3=x-2\]
OpenStudy (eliesaab):
\[
(y-8)^3=x-2
\]
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OpenStudy (rosepetalingg):
is that right..? lol
OpenStudy (eliesaab):
No
OpenStudy (rosepetalingg):
okay and then where do you go next from that?
OpenStudy (eliesaab):
\[
y^3-24 y^2+192 y-512=x-2
\]
OpenStudy (rosepetalingg):
okay but how did you get there?
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OpenStudy (eliesaab):
Use the formula
\[
(a-b)^3=a^3-3 a^2 b+3 a b^2-b^3
\]
OpenStudy (rosepetalingg):
okay and then after that do you just add the 2 to the other side to solve for x?
OpenStudy (eliesaab):
Yes
OpenStudy (rosepetalingg):
and then after that do you do anything else?
OpenStudy (eliesaab):
replace y by x to get the inverse function is
\[
g(x)=x^3-24 x^2+192 x-510
\]
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OpenStudy (rosepetalingg):
thats not one of my answer choices :(
OpenStudy (eliesaab):
What are your answer choices?
OpenStudy (eliesaab):
It could be the same thing since here we expanded
OpenStudy (rosepetalingg):
f-1(x)=(x-8)^3+2
f-1(x)=(x+8)^3+2
OpenStudy (rosepetalingg):
i have two more let me type them
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OpenStudy (eliesaab):
\[
(x-8)^3+2
\]
OpenStudy (rosepetalingg):
\[f^-1(x)=\sqrt[3]{x-8} +2\]
OpenStudy (eliesaab):
That is the same thing that I gave you where we expanded \((x-8)^3\)
OpenStudy (eliesaab):
The answer is \[
(x-8)^3 +2\]
OpenStudy (rosepetalingg):
okay thanks for your help
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OpenStudy (eliesaab):
You are very welcome