# Category Archives: Video Learning

### A-Maths: Differentiation Application - Stationary Value [Video]

I received this question on finding minimum gradient of a curve and it is confusing for many students as they probably lack the flexibility in seeing gradient beyond dy/dx.

I have presented this question in a slightly different manner by reducing the usage of  first derivative (dy/dx) and second derivative (d^2y/dx^2).

Check the 3 minutes video by clicking on the video to find out the step-by-step solutions and the explanations.

Video URL: https://youtu.be/K5-LaQUXo94

### A-Maths: Find Equation of Circle Given Tangent & Circle + More

Many students after reading the question take a long time to begin as they don't know how to start. The trick is to draw! Drawing helps us to see and understand the question better.

Drawing is one of the keys to answer this question. To answer part (a), we need to notice the property of radius is perpendicular to tangent. Also, in part (b) of the question, we need to apply discriminant from the topic of Quadratic.

I have shared my thinking process and step-by-step solutions in the following videos.

How did you find the videos? Did they help you to understand better? Leave me your feedback in the comment section.

Part (b) & (c) URL: Click here to watch part (b) & (c)  5 minutes.

### A-Maths: Full Derivation of R-formula

Last week, I taught my class on the topic of R-formula in A-Maths Trigonometry.

I highlighted that schools taught the usage of the two formulas as shown:

In my years of teaching, I have also come across schools which have insisted students to understand and use the full derivation of R-formula to solve the questions. Last night, my student who was sure that her school did not teach full derivation contacted me to help her as she was told at the very last minute that full derivation of R-formula will be tested in her test.

I have included the step-by-step working here. It includes the usage of addition formula and identity formula.

For those who prefer to hear from my explanation, I have included the video (duration: 6 minutes).

I would love to hear from you if you understand how R-formula is derived. Leave me your comment below.

### A-Maths: Factor-Remainder Theorem Introduction Videos

For many Secondary 3 A-Maths students, this topic called Factor - Remainder theorem or Polynomials is usually introduced in the first 3 months of the year.

In this topic, they are introduced to the method to find the factors of a cubic equation so that it can be solved. They also learnt when and how to use Remainder theorem to find the remainder when a dividend is divided by a divisor.

They also know to rewrite an expression into function f(x).

In the following two videos, I use less than 6 minutes to bring across the concepts of Factor theorem and Remainder theorem.

I hope through these videos, you will have a better understanding of these two concepts.

Also, I have included a page which contains all the O-Level Maths videos I have produced since 2007.

### A-Maths: Quadratic Equation - Sum & Product of Roots [video]

Quadratic Equation is an important topic in O-Level Elementary & Additional Maths.

Different areas are covered for each Math. For example in Additional Maths, we learnt:

• Discriminant
• Sum & product of roots
• Relationship between line and curve

I would like to share with you a question sent to me by a Secondary 3 student on sum & product of roots.

This topic is taught in the beginning for Secondary 3 Additional Maths.