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If log(x^2+y^2)=2tan^(-1)(y/x), show tha...

If `log(x^2+y^2)=2tan^(-1)(y/x),` show that `(dy)/(dx)=(x+y)/(x-y)` .

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Given,`log(x^2+y^2)=2tan^(-1)(y/x)`
`d/dx(log(x^2+y^2))=d/dx(2tan^(-1)(y/x))`
=`1/(x^2+y^2)​×d/dx​(x^2+y^2)=2×1/(1+(y/x)^2)​×(d/dx)​(y/x​)`
=`1/(x^2+y^2).(2x+2y(dy/dx))=2/(x^2+y^2)(x(dy/dx)-y)`
=`(2x+2y(dy/dx))=2(x(dy/dx)-y)`
=`x+y(dy/dx)​=x(dy/dx)​−y `
...
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RD SHARMA-DIFFERENTIATION-Solved Examples And Exercises
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  3. If log(x^2+y^2)=2tan^(-1)(y/x), show that (dy)/(dx)=(x+y)/(x-y) .

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  4. If y=cos^(-1)(2x)+2cos^(-1)sqrt(1-4x^2),-1/2<x<0 , find (dy)/(dx)

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  5. If sqrt(1-x^6)+sqrt(1-y^6)=a(x^3-y^3),p rov et h a t(dy)/(dx)=(x^2)/(...

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  6. If cos^(-1)((x^2-y^2)/(x^2+y^2))=tan^(-1)a , prove that (dy)/(dx)=y/xd...

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  14. If y=cos^(-1){xsqrt(1-x)+sqrt(x)sqrt(1-x^2)} and 0<x<1 find (dy)/(dx)

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  15. If y=sqrt(a^2-x^2) , prove that y(dy)/(dx)+x=0

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  16. If y=e^x+e^(-x),"p r o v et h a t"(dy)/(dx)=sqrt(y^2-4)

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  17. If y=sqrt(x^2+a^2) ,prove that y(dy)/(dx)-x=0

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  18. If y=xsin^(-1)x+sqrt(1-x^2), p rov et h a t(dy)/(dx)=sin^(-1)x

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  19. If y=1/2log((1-cos2x)/(1+cos2x)),p rov et h a t(dy)/(dx)=2cos e c2x

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  20. If y=e^xcosx ,p rov et h a t(dy)/(dx)=sqrt(2)e^xcos(x+pi/4)

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