Answer the following questions related to the discriminant of a quadratic equation:
(i) Define the discriminant of the quadratic equation ax2+bx+c=0.
(ii) State how the sign of the discriminant decides whether the equation has two distinct real roots, one repeated real root or no real roots.
(iii) A quadratic equation is said to have a repeated (coincident) root. What must be the value of its discriminant? Explain why.
(iv) If the discriminant of a quadratic equation is negative, explain why the graph of the corresponding quadratic polynomial does not intersect the x–axis.