Problem Solving using Vectors (Edexcel IAL Maths)

Spec point — 7.1

Problem solving using vectors

How are vectors used for problem solving?

• Vectors can be used to prove two lines are parallel(see Vector Addition)
• They can also be used to show points are collinear(lie on the same straight line)
• Vectors can be used to find missing vertices of a given shape
• You will need a good understanding of how to divide a line segment into a given ratio

When do I use trigonometry in vector problems?

• When problem-solving with vectors, trigonometry can help us:

  • convert between component form and magnitude/direction form (see Magnitude Direction)
  • find the angle between two vectors using Cosine Rule(see Non-Right-Angled Triangles)
  • find the area of a triangle using a variation of Area Formula(see Non-Right-Angled Triangles)

Exam Hint

• Think of vectors like a journey from one place to another – you may have to take a detour eg. A to B might be A to O then O to B.
• Diagrams can help, if there isn’t one, draw one. For a given diagram labelling all known vectors and quantities will help.

Worked Example