Weekly Question

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 (a) URL: Click here to watch part (a) 7 minutes

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

A-Maths: Application Question on Modulus Graph

Based on my observations on recent mid-year exams papers, prelims papers, it seems like many schools are setting highly application questions for many topics. In this post, I would like to share with you an example of how modulus graph can be tested by applying our basic concepts on equations of lines.

I have been reminding my students to keep their mind open to 'new - trend' questions which might require their fast thinking on the spot so we keep our mind flexible when we do our O-Level examinations.

I hope you learn useful concepts and thinking skills on this question. Do leave me a comment if you have any other questions.

E-Maths: Problems on Compound Interest

O Level Maths Tuition Formula to calculate total amount in a compound interest question is provided in GCE O-Level E-Maths examinations so students don't have to memorise.

It is therefore important for students to know how to use the compound interest formula.

Notice in these two questions, the frequency of compounding affects the value of r and n so it affects the total amount as well.

I always share with my students in my weekly O-Level Maths tuition classes to put themselves in the shoes of a banker who helps their client to grow their money. The frequency of compounding is just like the frequency they meet their client and at each meeting they need to inform how much rate their money has grown based on the frequency of compound.

The Exclamation Mark ! in Binomial Theorem

factorial-sign-binomial Binomial Theorem came out as a 9 marks question in 2009 GCE 'O' Level Additional Mathematics Paper (Subject Code: 4038) so you know as well as I do the importance of Binomial.

Read about other useful posts on Binomial Theorems:

Binomial Expansion Teaches how to choose the RIGHT partner (:

A-Math Binomial Expansion: Finding Term Independent of x By A Shortcut Method

Exam Question : Usage of Binomial Formula

I'm looking at the question now. It is testing on the usage of the Binomial formula, including the 'n choose r' formula. Many students call this sign: '!' 'exclamation mark' which is known correctly as factorial.

I will be using the following question to illustrate how to simplify the 'n choose r' formula without memorizing. (I understand some schools want students to memorize)

Let's begin by understanding what's 'n choose r' all about:

n-choose-r-binomial — Click on image for larger view

Do you know how to simplify 'n choose 3'?

Here's the question which requires us to apply what we have discussed. I would suggest you attempt it on your own before clicking here for the solution.

E-Math: What is Direct Proportion and Inverse Proportion?

Proportion is a topic taught in Secondary 1 and 2. In fact, we have learnt about direct proportion much younger.

DIRECT PROPORTION

A real simple example of Direct Proportion would be the more money I have, the more things I can buy. When amount of money increases, the number things I can buy increase too. (Notice the increase in both things)

Another example, the less I eat, the thinner I become, so as the amount of food eaten decreases, my weight decreases too.

INVERSE PROPORTION

An example of inverse proportion most of you can relate to would be: the more time I spent on Facebook (PSP, WII, Internet), the less time I have on my books!

Allow me to add in another example of Inverse Proportion, the more I spent, the less I have in my bank.

These are some examples (simple) to understand the true meaning of Direct or Inverse proportion.

In the next post, I will be sharing with you how we can translate a statement into an equation involving proportion. I'm also going to highlight the 'tricky' proportion question in 2008 GCE O Level Elementary Mathematics Paper 1.

A-Math: Differentiation & Integration Application : Examples of Typical Kinematics Questions

I was looking through 2008 GCE O Level Additional Mathematics Exam Papers (Subject Code: 4038) and as expected, there was a Kinematics question (worth 6 marks) in Paper 1.

Kinematics is a application topic for Differentiation and Integration. To master this topic, you do not necessarily need to bring in your physics knowledge though it could be useful at times.

Instead, how I get my students to be a master in this topic is to be familiarize with a KINEMATICS VOCABULARY LIST.

Here's some of the vocabulary words that are useful and common:

Momentarily at rest, instantaneously at rest, changes direction of motion, stationary
Initial displacement, initial velocity, initial acceleration
Greatest displacement, greatest velocity, greatest acceleration
Distance travelled in the 4th second VS Distance travelled in the first 4 seconds
Maximum distance from Point O
Particle returns to Point O
Constant Velocity

I would say for Kinematics, it is one of the few topics in A-Math which uses extensive vocabulary. This is also the reason for you to decipher the meaning behind these words.

So do you know the meaning behind these words? I would love to hear about it in the comments section.

I have also taken a few questions from my A-Math TREQ book (Topical Real Exam Questions) to illustrate some common exam questions on Kinematics, further highlighting the importance of knowing your Kinematics well. (Click on the image for bigger view)

I would be sharing the step by step solutions for Question 8 in the next post. Subscribe to my blog to be updated again!