Iteration

There are 23 NRICH Mathematical resources connected to Iteration
Rain or Shine
problem
Favourite

Rain or shine

Age
16 to 18
Challenge level
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Predict future weather using the probability that tomorrow is wet given today is wet and the probability that tomorrow is wet given that today is dry.
Climbing Powers
problem
Favourite

Climbing powers

Age
16 to 18
Challenge level
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$2\wedge 3\wedge 4$ could be $(2^3)^4$ or $2^{(3^4)}$. Does it make any difference? For both definitions, which is bigger: $r\wedge r\wedge r\wedge r\dots$ where the powers of $r$ go on for ever, or $(r^r)^r$, where $r$ is $\sqrt{2}$?
A Very Shiny Nose?
problem

A very shiny nose?

Age
16 to 18
Challenge level
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This problem explores the biology behind Rudolph's glowing red nose, and introduces the real life phenomena of bacterial quorum sensing.
Difference Dynamics
problem

Difference dynamics

Age
14 to 18
Challenge level
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Take three whole numbers. The differences between them give you three new numbers. Find the differences between the new numbers and keep repeating this. What happens?
Archimedes Numerical Roots
problem

Archimedes numerical roots

Age
16 to 18
Challenge level
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How did Archimedes calculate the lengths of the sides of the polygons which needed him to be able to calculate square roots?
Triangle Incircle Iteration
problem

Triangle incircle iteration

Age
14 to 16
Challenge level
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Keep constructing triangles in the incircle of the previous triangle. What happens?
Loopy
problem

Loopy

Age
14 to 16
Challenge level
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Investigate sequences given by $a_n = \frac{1+a_{n-1}}{a_{n-2}}$ for different choices of the first two terms. Make a conjecture about the behaviour of these sequences. Can you prove your conjecture?
Differs
problem

Differs

Age
11 to 14
Challenge level
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Choose any 4 whole numbers and take the difference between consecutive numbers, ending with the difference between the first and the last numbers. What happens when you repeat this process over and over again?
Converging Means
problem

Converging means

Age
14 to 16
Challenge level
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Take any two positive numbers. Calculate the arithmetic and geometric means. Repeat the calculations to generate a sequence of arithmetic means and geometric means. Make a note of what happens to the two sequences.