At the point (pi/3,pi/3)(π3,π3), we get
tan(2pi/3)/tan^2(pi^2/9)=Ctan(2π3)tan2(π29)=C
=> -sqrt(3)/tan^2(pi^2/9)=C⇒−√3tan2(π29)=C
=> C~~-0.45623⇒C≈−0.45623
So then we can rewrite CC on the right hand side like this
tan(2x)/tan^2(xy)=-0.45623tan(2x)tan2(xy)=−0.45623
Cross multiply
tan(2x)=-0.45623tan^2(xy)tan(2x)=−0.45623tan2(xy)
Next, we can implicitly differentiate each side
d/dx(tan(2x))=-0.45623d/dx(tan^2(xy))ddx(tan(2x))=−0.45623ddx(tan2(xy))
2sec^2(2x)=-0.45623(2tan(xy)sec^2(xy)(x(dy)/(dx)+y))2sec2(2x)=−0.45623(2tan(xy)sec2(xy)(xdydx+y))
Now we can plug in the point (pi/3,pi/3)(π3,π3) and solve for dy/dxdydx
2sec^2(2pi/3)=-0.45623(2tan(pi/3*pi/3)sec^2(pi/3*pi/3)(pi/3(dy)/(dx)+pi/3))2sec2(2π3)=−0.45623(2tan(π3⋅π3)sec2(π3⋅π3)(π3dydx+π3))
After a little work with a calculator, you get
dy/dx=-1.89585dydx=−1.89585