Why (-1)(-1) = 1?

Why (-1)(-1) = 1?

Two methods shown.

1. Use of distributive law

2. Use of the Rule of Indices

Some discussions are given to illustrate the use of negative numbers.

Polygons

Sum of Interior Angles of A Polygons

There are 4 different proofs shown here. I am sure students will enjoy them.

International Standard Book Number

International Standard Book Number
This article is written for Thai students of Prichai Ratanakorn School from Ranong.

Square root of Complex Nos with Pythagorean Triples

Square root of Complex Numbers with Pythagorean Triples

This post is dedicated to Lower Six B of Penang Free School (Year 2010).

British Math Olympiad 2008

British Math Olympiad 2008 Paper 1 / Question 5 - Solution

A geometrical property is proved using some algebraic identities.

British Math Olympiad 2008

British Math Olympiad 2008 Paper 1 / Question 4 - Solution

If n objects are put into p pigeon holes, where p < n then some pigeonhole must contain at least two objects.

British Math Olympiad 2008

British Math Olympiad 2008 Paper 1 / Question 3 - Solution

This is a geometrical problem solved using circle theorems.

British Math Olympiad 2008

British Math Olympiad 2008 Paper 1 / Question 2 - Solution

I have fun solving this question. Enjoy!

British Math Olympiad 2008

British Math Olympiad 2008 Paper1 - Question1 / Solution

I took the chance to solve some problems in the BMO paper 2008. During the CNY holidays when I was quite free so I typed out the solution for the first question. I shall find time to type more later.

A Little Creative Question

A Little Creativity Appeals

Hope you enjoy doing the problem.

Snell's Law - A Mathematical Proof

Snell's law - A Mathematical Proof

The use of dy/dx = 0 to determine maximum or minimum value in the proof of Snell's Law , I hope will appeal to students studying math and physics for SPM/STPM.

Pythagoras Theorem

Pythagoras Theorem - Proof by Leonardo da Vincci

A very elegant proof which I admire and you will be equally fascinated. There are other proofs that may be very different but they have their merits of their own. Hope to post some in future.