Mathematics 0580 · IGCSE · Sequences

Sequences — practice question

The first four diagrams in the sequence are shown here. Each diagram is formed using white dots and black dots.
(a)[2]

Complete the table entries for Diagram 5 and Diagram 6.

(b)[1]

Write an expression, in terms of $n$, for how many white dots there are in Diagram $n$.

(c(i))[1]

Determine the total number of dots in Diagram 8.

(c(ii))[2]

Find an expression for the number of black dots in Diagram $n$, and give your answer in its simplest form.

(d)[5]

Find the values of $a$ and $b$. You must show all of your working.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: Values arranged correctly

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI