September 2002, Stage 4&5

Problems

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LOGO Challenge 2 - Diamonds Are Forever

Stage: 2, 3 and 4 Challenge Level: Challenge Level:1

The challenge is to produce elegant solutions. Elegance here implies simplicity. The focus is on rhombi, in particular those formed by jointing two equilateral triangles along an edge.

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Enriching Experience

Stage: 4 Challenge Level: Challenge Level:1

Find the five distinct digits N, R, I, C and H in the following nomogram

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Euler's Officers

Stage: 4 Challenge Level: Challenge Level:1

How many different ways can you arrange the officers in a square?

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Parallel Universe

Stage: 4 Challenge Level: Challenge Level:2 Challenge Level:2

An equilateral triangle is constructed on BC. A line QD is drawn, where Q is the midpoint of AC. Prove that AB // QD.

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Really Mr. Bond

Stage: 4 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

115^2 = (110 x 120) + 25, that is 13225 895^2 = (890 x 900) + 25, that is 801025 Can you explain what is happening and generalise?

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Seriesly

Stage: 5 Challenge Level: Challenge Level:1

Prove that k.k! = (k+1)! - k! and sum the series 1.1! + 2.2! + 3.3! +...+n.n!

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Cubic Spin

Stage: 5 Challenge Level: Challenge Level:2 Challenge Level:2

Prove that the graph of f(x) = x^3 - 6x^2 +9x +1 has rotational symmetry. Do graphs of all cubics have rotational symmetry?