5 resources.
Slopes and equations of tangent and normal lines to a curve, special cases, five worked examples including a tangent parallel to a given line, a graph and common mistakes.
Position vectors and head-minus-tail, the section formula internally and externally, midpoints, centroids and collinearity, with worked examples.
Line segment, ray and line: the differences, collinear points and concurrent lines, Euclid's axiom about lines through two points, linear pairs of angles, counting segments, and common mistakes.
The area of a triangle from its vertices using a determinant, with worked examples, a collinearity test, finding an unknown vertex from a given area, and common mistakes.
Area of a triangle and parallelogram using vectors: the cross product formulas, worked examples from vertices, sides and diagonals, a check against the determinant formula, and common mistakes.