Year 1994 - Volume 30
2020 - Present

George Szekeres and David Tacon
The diagram on the cover of this magazine illustrates the reflecting property of the parabola: light rays which are parallel to the axis of the parabola are reflected by the parabola in such a way that they pass through a common point.

David Angell
We'll look at a few two-player games, each of which can be broadly described as follows:

Peter Brown
Mathematics can at times appear fairly dull and routine. Solving 30 quadratic equations, finding the hypotenuse of seemingly endless right triangles and differentiating even more functions can be downright boring!

Q.913 S is a collection of numbers. At least half of the numbers in S are even, at least two thirds are multiples of 3 , and at least six sevenths are multiples of 7 . Prove that at least one of the numbers in S is a multiple of 42 .

Q.903 Find all positive integers n such that 1+2+3+⋯+n is a factor fo 1×2×3×⋯×n . .

Lisa Gotley While browsing through the science section of our local A.B.C. bookshop, I leafed through the autobiography of Richard Feynman (1918-1988) titled 'Genius' by James Gleick.

Peter Brown
Mathematics is full of unsolved problems and conjectures which attract the minds of many people, both amateurs and professionals.

David Tacon
Although there is a formula for solving cubic equations (see Parabola, 2nd issue 1989) it is rarely used in practice since it can be tricky to apply in even very simple cases.

1. A large number of brown, green and yellow frogs are wandering around on an island.

Q.923 On and island there are 50 brown, 57 green, 62 yellow and 68 red frogs.

Q.913 S is a collection of numbers. At least half of the numbers in S are even, at least two thirds are multiples of 3 and at least two thirds are multiples of three, and at least six sevenths are multiples of 7 .

Byron Walden
David Angell's recent article on addition games reminded me of a number game called the Divisor Game.

Peter Brown
The ancient Greeks thought about numbers in quite a different way to us.

Bill McLean
Many mathematical functions are not readily computable using only a finite sequence of elementary arithmetic operations.

V. Jeyakumar and B.M. Glover
In this short article we will introduce some important notions concerned with the class of convex functions.

Q.931 In a large flat area of bushland there are two fire-spotting towers, one exactly 20km east of the other.

Q.923 On an island there are 50 brown, 57 green, 62 yellow and 68 red frogs.