Kuala Lumpur Trial 2025 Add Maths Paper 1, Question 9Vectors

Solved on video in English · Form 4, Vectors · 4:40 video

The question

(a)

Diagram 4 shows two vectors OA and OB. Express AB in the form xi + yj.

(b)

Given that MN = 2a + hb is parallel to PQ = 5a − b. Find the value of h.

Step 1

Use the route AB = AO + OB = −OA + OB.

Why this step

AB isn't given directly, so we travel A to O, then O to B. Writing OA − OB instead (wrong direction) is the classic slip.

2 more steps, each with the reason for it, in the full solution

Final answer

AB = −4i − 2j

Where students lose marks

Watch out: AB = OB − OA (end minus start), not OA − OB. When you subtract OA, flip the sign of both terms.

3 more steps, each with the reason for it, in the full solution

Final answer

h = −2/5

Where students lose marks

Watch out: keep the −b in PQ = 5a − b. The b-part becomes −λ, so h = −2/5, not +2/5.

Watch every step of this question solved on video (4:40), with the reason behind each step and a box that checks your own answer.

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