Consider a triangle with vertices (x1,y1), (x2,y2) and (x3,y3).
(i) State the relationship between the numerical value of the determinant formed by these three points and the area of the triangle.
(ii) Keeping (x1,y1) and (x2,y2) fixed, the x-coordinate of the third vertex is multiplied by a non-zero constant k while the y-coordinate remains unchanged. Explain how the area of the triangle changes in terms of k.
(iii) The third vertex now moves along the line segment joining (x3,y3) to another point (x4,y4) such that its position vector is t(x3,y3)+(1−t)(x4,y4), where 0≤t≤1. Describe how the area of the resulting triangle varies with t.