Mathematics
5 Online
OpenStudy (anonymous):
Differentiate the inverse trig function.
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OpenStudy (anonymous):
\[\sqrt{x^2-1}arcsecx\]
hartnn (hartnn):
product rule (uv), aware of that ?
OpenStudy (anonymous):
yes, but the sqrt(x^2-1), does that need to be chain ruled somehow?
hartnn (hartnn):
yup, chain rule is required there
OpenStudy (anonymous):
\[\sqrt{x^2-1}(\frac{ 1 }{x \sqrt{x^2-1} })+\sec^{-1}(\frac{ 1 }{ 2 }(x^2-1))^{-1/2}\]
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OpenStudy (anonymous):
that cant be right
OpenStudy (anonymous):
so, if i chain rule
hartnn (hartnn):
what did u do in 2nd term ?
hartnn (hartnn):
1st term is correct, and u can cancel something there, what ?
OpenStudy (anonymous):
\[\frac{ 1 }{ 2 }(x^2-1)^{-1/2}(\sqrt{x^2-1})(\frac{ 1 }{ x \sqrt{x^2-1} }) + arcsecx \frac{ 1 }{ 2 }(x^2-1)^{-1/2}\]
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OpenStudy (anonymous):
is that the chain rule?
hartnn (hartnn):
no...
hartnn (hartnn):
first , did u apply product correctly?
OpenStudy (anonymous):
fg'+gf'
OpenStudy (anonymous):
f = sqrt(x^2-1) g=arcsecx
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hartnn (hartnn):
g= arcsec x right ?
hartnn (hartnn):
ok,
so what is fg' = ?
OpenStudy (anonymous):
\[\sqrt{x^2-1}(\frac{ 1 }{ x \sqrt{x^2-1} })\]
hartnn (hartnn):
can u cancel something ?
OpenStudy (anonymous):
which is 1/x
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hartnn (hartnn):
yes!
to be precise its 1/|x|
so now you are completely done with fg'
it equals 1/|x|
now what is gf' ?
OpenStudy (anonymous):
\[arcsecx(\frac{ 1 }{ 2 }(x^2-1))^{-1/2}(2)\]
OpenStudy (anonymous):
chain rule ok?
hartnn (hartnn):
2 or 2x in the end ?
hartnn (hartnn):
yes, chain rule applied correctly.
but d/dx(x^2-1) is 2 or 2x ??
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OpenStudy (anonymous):
oh 2x my bad
OpenStudy (anonymous):
:0
hartnn (hartnn):
now put everything together
fg'+f'g =?
hartnn (hartnn):
remember to cancel 2 from numerator and denominator of 2nd term
OpenStudy (anonymous):
\[\frac{ 1 }{ |x| }+\frac{ 2xarcsecx }{ 2\sqrt{x^2-1} }\]
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hartnn (hartnn):
*2 can be cancelled*
OpenStudy (anonymous):
oh ya duh :)
hartnn (hartnn):
so, did u get your required final answer ?
OpenStudy (anonymous):
\[\frac{\sqrt{x^2-1}+xarcsecx }{ x \sqrt{x^2-1} }\]
hartnn (hartnn):
wouldn't it be x^2 in numerator ? before arc....
you could have left it in 2 terms form also
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OpenStudy (anonymous):
oh ya, so its x^2arcsecx
OpenStudy (anonymous):
forgot to cross multiply the x
OpenStudy (anonymous):
is that it though?
hartnn (hartnn):
yup, thats it.
OpenStudy (anonymous):
!!!!!
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OpenStudy (anonymous):
@hartnn you saved the day yet again!!! :)
hartnn (hartnn):
as usual...welcome ^_^
OpenStudy (anonymous):
\[\frac{ \sqrt{x^2-1}+x^2arcsecx }{ x \sqrt{x^2-1} }\]
hartnn (hartnn):
yup.
OpenStudy (anonymous):
weeew! thanks so much!!!