asked 35.5k views
2 votes
Find
(dy)/(dx) when
\tt {x}^(2) + {y}^(2) = sin \: xy

Please help! :)
Thanks in advance!! ​

1 Answer

7 votes

Answer:


\boxed{\bold{ \tt (dy)/(dx)=(2x-y cos\: xy)/(x*cos \:xy-2y)}}

Explanation:


\tt x^2+y^2=sin xy

Differentiating both sides with respect to x.


\tt{(d)/(dx)(x^2+y^2)=(d)/(dx)(sin xy)}

Using the Addition rule, Power rule, chain rule, and Product rule respectively.


\bold{\tt (d)/(dx)x^2+(d)/(dx){y^2}= (d sin xy)/(dxy)*(dxy)/(dx)}


\bold{\tt2x^(2-1)+(d y^2)/(dx)*(dy)/(dx)=cosxy*(y*(dx)/(dy)+x(dy)/(dy)*(dy)/(dx))}


\bold{ \tt2x+2y(dy)/(dx)= cos xy*(y+x*(dy)/(dx))}


\bold{ \tt2x+2y(dy)/(dx)=y cos\: xy+x(dy)/(dx)*cos \:xy}

Solving for
\tt (dy)/(dx)


\bold{ \tt2x-y cos\: xy=x(dy)/(dx)*cos \:xy-2y(dy)/(dx)}


\bold{ \tt x(dy)/(dx)*cos \:xy-2y(dy)/(dx)=2x-y cos\: xy}

Taking common
\tt (dy)/(dx)


\bold{ \tt (dy)/(dx)(x*cos \:xy-2y)=2x-y cos\: xy}

Solving for
\tt (dy)/(dx)


\bold{ \tt (dy)/(dx)=(2x-y cos\: xy)/(x*cos \:xy-2y)}

Therefore, Answer is
\boxed{\bold{ \tt (dy)/(dx)=(2x-y cos\: xy)/(x*cos \:xy-2y)}}

Note: Formula


\boxed{\bold{\tt{Addition \: Rule:(d)/(dx)(x^n+y^n) =(d)/(dx)*x^n+(d)/(dx)*y^n}}}


\boxed{\bold{\tt{Power \: Rule:(d)/(dx)x^n =n*x^(n-1)}}}


\boxed{\bold{\tt{Chain \:\: Rule: (d)/(dx)y^n=(d)/(dy)y^n(dy)/(dx)=n*y^(n-1)(dy)/(dx)}}}


\boxed{\bold{\tt{Product\:Rule:(d)/(dx)(u*v)=(du)/(dx)*v+u*(dv)/(dx)}}}

answered
User Mafso
by
8.4k points
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