Student work

One student suggested the series \(1+ \tfrac{1}{2}+ \tfrac{1}{4}+ \tfrac{1}{8}+ \tfrac{1}{16}+\dotsb\) for part (a) because she knew that its sum is \(2\). Here is some of her work for part (c).

Here are this student’s initial notes as she tackled part (c).

hand written thoughts including modify it? reverse it? gap needs to get smaller, graph it

  • How could you use these suggestions to find a series that satisfies the constraints in part (c)?

  • Can you suggest any other ways to tackle part (c)?

The student then used some of these ideas, leading to the following sketch graph.

sketch graph showing negative terms getting closer to zero, labelled a reflection of 1+half+quarter...

  • What series is this student suggesting?

  • How do you think this student has used her initial thoughts to get to this series?

  • What other series could she have obtained using her initial ideas?