This tag is for questions relating to "implicit function", a function or relation in which the dependent variable is not isolated on one side of the equation.
The notion of implicit function is of utmost importance while solving real-life problems.
A function in which the dependent variable, and independent variable(s) are not separated (isolated) on opposite sides of the equality are known as implicit function.
i.e., If it only has the form $~f(x,y)=0~$, then it is implicit.
e.g., Take $~x^2 + xy~ – y^2 = 1~$, then $~f(x,y)=x^2 + xy~ – y^2-1=0~$.
Reference: