tan(x-y)=y/(3+x^2)tan(x−y)=y3+x2
Take the derivative of both sides.
d/dx(tan(x-y))=d/dx(y/(3+x^2))ddx(tan(x−y))=ddx(y3+x2)
Solve.
d/dx(tan(x-y))=(1-dy/dx)(sec^2(x-y))ddx(tan(x−y))=(1−dydx)(sec2(x−y))
d/dx(y/(3+x^2))=((3+x^2)(dy/dx)-(y)(2x))/(3+x^2)^2ddx(y3+x2)=(3+x2)(dydx)−(y)(2x)(3+x2)2
Now we know:
(1-dy/dx)(sec^2(x-y))=((3+x^2)(dy/dx)-(y)(2x))/(3+x^2)^2(1−dydx)(sec2(x−y))=(3+x2)(dydx)−(y)(2x)(3+x2)2
We can simplify
(1-dy/dx)(sec^2(x-y))(3+x^2)^2=((3+x^2)(dy/dx)-(y)(2x))(1−dydx)(sec2(x−y))(3+x2)2=((3+x2)(dydx)−(y)(2x))
((sec^2(x-y))(3+x^2)^2-(dy/dx)(sec^2(x-y))(3+x^2)^2)=((3+x^2)(dy/dx)-(y)(2x))((sec2(x−y))(3+x2)2−(dydx)(sec2(x−y))(3+x2)2)=((3+x2)(dydx)−(y)(2x))
((sec^2(x-y))(3+x^2)^2+(y)(2x))=((3+x^2)(dy/dx)+(dy/dx)(sec^2(x-y))(3+x^2)^2)((sec2(x−y))(3+x2)2+(y)(2x))=((3+x2)(dydx)+(dydx)(sec2(x−y))(3+x2)2)
((sec^2(x-y))(3+x^2)^2+(y)(2x))=(dy/dx)((3+x^2)+(sec^2(x-y))(3+x^2)^2)((sec2(x−y))(3+x2)2+(y)(2x))=(dydx)((3+x2)+(sec2(x−y))(3+x2)2)
((sec^2(x-y))(3+x^2)^2+(y)(2x))/((3+x^2)+(sec^2(x-y))(3+x^2)^2)=dy/dx(sec2(x−y))(3+x2)2+(y)(2x)(3+x2)+(sec2(x−y))(3+x2)2=dydx
Depending on how simplified the answer needs to be, this is technically the solution.