The region represented by
{z = x + iy $$ \in $$ C : |z| – Re(z) $$ \le $$ 1} is also given by the
inequality : {z = x + iy $$ \in $$ C : |z| – Re(z) $$ \le $$ 1}

The negation of the Boolean expression p $$ \vee $$ (~p $$ \wedge $$ q) is equivalent to :

The general solution of the differential equation

$$\sqrt {1 + {x^2} + {y^2} + {x^2}{y^2}} $$ + xy$${{dy} \over {dx}}$$ = 0 is :

(where C is a constant of integration)

Let L₁ be a tangent to the parabola y² = 4(x + 1)
and L₂ be a tangent to the parabola y² = 8(x + 2)
such that L₁ and L₂ intersect at right angles. Then L₁ and L₂ meet on the straight line :