Mathematics
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OpenStudy (anonymous):
\[2x \sqrt{36-x ^{2}} \] Solve the area equation for x=3
HELP ME SOLVE!!!
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OpenStudy (anonymous):
write
\[2\times 3\times \sqrt{36-3^2}\] and compute
OpenStudy (anonymous):
\[6\sqrt{36+9}\]
OpenStudy (anonymous):
@satellite73 ^ ?
OpenStudy (anonymous):
no
OpenStudy (anonymous):
\[36-3^2=36-9=27\]
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OpenStudy (anonymous):
so would it be 12\[\sqrt{5}\]
OpenStudy (anonymous):
lets go slow
OpenStudy (anonymous):
12\[\sqrt{5}\]
OpenStudy (anonymous):
the first step is \[2\times 3\times \sqrt{36-3^2}\]
OpenStudy (anonymous):
then you compute and get
\[6\sqrt{27}\] because \(36-9=27\)
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OpenStudy (anonymous):
Ok, this helps going step by step.
OpenStudy (anonymous):
since \(27=9\times 3\) you have \(\sqrt{27}=\sqrt{9}\times \sqrt{3}\) giving \[\sqrt{27}=3\sqrt{3}\]
OpenStudy (anonymous):
Would you then multiply the 3 and 6?
OpenStudy (anonymous):
so now you have
\[6\times 3\sqrt{3}=18\sqrt{3}\] as a final answer
OpenStudy (anonymous):
yes
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OpenStudy (anonymous):
Blah! Now the next part is awfully tricky.
OpenStudy (anonymous):
A(x)=2x\[\sqrt{36-x ^{2}}\]
OpenStudy (anonymous):
x=\[\sqrt{3}\]
OpenStudy (anonymous):
@satellite73 What about this?
OpenStudy (anonymous):
\[A(x)=2x\sqrt{36-x^2}\]
\[A(\sqrt3)=2\sqrt{3}\times \sqrt{36-(\sqrt{3})^2}\]
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OpenStudy (anonymous):
you get
\[A(\sqrt{3}=2\sqrt{3}\sqrt{36-3}=2\sqrt{3}\sqrt{33}=2\sqrt{66}\]
OpenStudy (anonymous):
okay i made a mistake
OpenStudy (anonymous):
How did you end up with 66 inside the square root? I'm new to all of this. :-/
OpenStudy (anonymous):
it is
\[2\sqrt{3}\sqrt{33}=2\sqrt{99}\]
OpenStudy (anonymous):
yeah i was wrong
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OpenStudy (anonymous):
\[\sqrt{a}\sqrt{b}=\sqrt{ab}\]
OpenStudy (anonymous):
How did you get the 99, just multiply 3 and 33?
OpenStudy (anonymous):
and \(3\times 33=99\)
OpenStudy (anonymous):
yes
OpenStudy (anonymous):
but you are still not done
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OpenStudy (anonymous):
Ok, let's move forward.
OpenStudy (anonymous):
since \(99=9\times 11\) you get
\[\sqrt{99}=\sqrt{9}\sqrt{11}=3\sqrt{11}\]
OpenStudy (anonymous):
for a final answer of
\[6\sqrt{11}\]
OpenStudy (anonymous):
This material is complicated.
OpenStudy (anonymous):
Thank you for helping. :)
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OpenStudy (anonymous):
yw