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Mathematics 16 Online
OpenStudy (eamier):

f(x,y)=sin inverse (y/x).|x|>|y| i want to differentiate by x.

OpenStudy (eamier):

retype question: \[f(x,y)=\sin^{-1}\frac{y}{x}\]

OpenStudy (eamier):

i got this answer:\[-\frac{y}{x \sqrt(x^2-y^2)}\]

OpenStudy (eamier):

but the answer in book is:\[-\frac{|x|y}{x^2 \sqrt(x^2-y^2)}\]

OpenStudy (anonymous):

@eamier

OpenStudy (eamier):

yes

OpenStudy (anonymous):

wait a second...

OpenStudy (eamier):

if i substitute x by value like 2 or -2 its answer is same.. so why we need |x|

OpenStudy (anonymous):

by definition... \[\left| x \right|=x,x>0\] and -x,x<0

hartnn (hartnn):

but in the numerator , you actually get \(\sqrt {x^2}\) , right ? which you wrote it as x, isn't it. actually \(\sqrt {x^2}=|x|\)

OpenStudy (eamier):

yes i see..

hartnn (hartnn):

\(\sqrt {\dfrac{ {x^2-y^2}}{x^2}}=\dfrac{\sqrt{x^2-y^2}}{|x|}\) ok :)

OpenStudy (eamier):

thank you..

hartnn (hartnn):

welcome ^_^

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