I'm very excited to be working on the revised copy for the **GCE O-Level Additional & Elementary Mathematics Ten Years Series (2003-2012)** by FBP Publisher.

The book should be available in all Popular bookstores (Singapore) in early April. There's something new on this book. To provide more value to students, this year we have included an additional book of drill questions.

I would like to share one of the questions from **Differentiation: Tangent & Normal **with all of you.

**Skill required:**

- Quotient rule
- Gradient of curve is dy/dx

**Bonus:** Strictly decreasing function means dy/dx < 0 for all values of *x.*

Click on the image for a bigger view.

I would like to hear any comments from you. Did you do this question using another approach? Leave me a comment.