What is the slope of the tangent line of tan(2x)/tan^2(xy)= C tan(2x)tan2(xy)=C, where C is an arbitrary constant, at (pi/3,pi/3)(π3,π3)?

1 Answer
Jul 5, 2017

dy/dx=-1.89585dydx=1.89585

Explanation:

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)=C3tan2(π29)=C

=> C~~-0.45623C0.45623

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(π3π3)sec2(π3π3)(π3dydx+π3))

After a little work with a calculator, you get

dy/dx=-1.89585dydx=1.89585