SPM 2023 Add Maths Paper 1, Question 1Progressions

Solved on video in English and Bahasa Melayu · Form 4, Progressions · 3:47 video

The question

(a)

It is given that four consecutive terms of a sequence are 50, 45, x and y. State the value of (a) y − x if the sequence is an arithmetic progression.

(b)

State the value of (b) y/x if the sequence is a geometric progression.

Step 1

For an arithmetic progression the common difference d = T₂ − T₁ = 45 − 50 = −5.

Why this step

In an AP the same amount is added each step, so any term minus the one before it gives d. Always do later minus earlier.

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

Final answer

y − x = −5

Where students lose marks

Watch out: y − x means later minus earlier, so it is 35 − 40 = −5. Writing x − y gives +5, the wrong sign.

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

Final answer

y/x = 9/10 (= 0.9)

Where students lose marks

Watch out: part (b) is a new sequence. Don't reuse x = 40 and y = 35 from part (a); use the common ratio 9/10.

Watch every step of this question solved on video (3:47), with the reason behind each step and a box that checks your own answer.

No card. Every past-year question on video, in English and BM.