Paddy MacMahon

@paddymacmahon.com

1340 Followers 476 Following

Head of Maths at Latymer Upper School paddymacmahon.com OCR, Cambridge International and AQA associate, Desmos and Google Colab enthusiast

The cover of The Death of Us by Abigail Dean: a sunlit room with a single wooden chair and a woman's shadow on the wall behind it. Less clearly, a man's shadow next to it.
A floor tiling with a start made from 12 equilateral triangles inside two concentric circles.
A picture of the book 'Making Sense: teaching and learning mathematics with understanding'.
An extract from the GCSE choices booklet for King Edward's Grammar School, Chelmsford, available at https://www.kegs.org.uk/wp-content/uploads/2025/02/GCSE-Options-Booklet-for-September-2026.pdf
A weather forecast for Ávila, showing sunshine and 35°C temperatures
A derivation of E(X²) for a geometric distribution.
A projected local election result for Ealing Broadway, showing Greens in the lead over the Conservatives.
The cover of "Confessions" by Catherine Airey, showing a b&w photo of a young woman holding a kitten on a city street.
A departmental timetable for maths.
The graph of y=ke^(kx) is shown in red, together with the tangent to the curve that passes through the origin, in blue. The area enclosed by the curve, the tangent and the x-axis is shaded green.
A cartoon of a head teacher and prospective parent and child outside a school. The head is saying: "It's an excellent catchment area... none of the teachers can afford to live here"
A picture from an aircraft window of dark circles and sectors in the sand, west of the Nile in Egypt.
A pair of somali crows on a blue frame silhouetted against a cloudy sky.
A picture of a lion, camel (killed by the lion) and other animals under an acacia tree. There's a hyena with a geometric series spurting from his head.
A male shining sunbird calling from an acacia tree.
An Abyssinian white-eye grooming its mate on an acacia branch.
A Speke's Gazelle next to a small acacia bush.
A sign in Sheikh, Somaliland: Pearson Exam Centre
A whiteboard with some normal distribution graphs and questions.
A pair of binoculars and a camera with two books: the Bradt guide to Somaliland and a field guide to the Birds of the Horn of Africa.
A template for conclusion to a hypothesis test.
The graph of sqrt x + sqrt y = 1 is shown in red in the first quadrant. Also in red is the circle which touches this curve and both axes and lies between the curve and the axes. The region under the curve but outside the circle is shaded green.
A packet of M&Ms arranged as a bar chart by colour next to the empty bag. There are unusually (?) many orange M&Ms...
A sheet on the normal distribution using rules of thumb for proportions within 1, 2 or 3 standard deviations of the mean. There are three diagrams: one showing 68% of the distribution within 1 sd, a second showing 95% of the distribution within 2sd, and a third showing almost 100% within 3sd. Then there are 4 questions: 1. Masses of adult females of a species of dolphin are normally distributed with mean 220 kg and standard deviation 18 kg. What proportion of female dolphins of this species are between 202 kg and 256 kg in weight? 2. Heights of leprechauns are normally distributed with a mean of 1.2 m. 16 % of leprechauns are over 1.3 m tall. What proportion of leprechauns are under 1 m tall? 3. Harriet is studying a species of lizard. 2.5 % of them have masses under 20g, and 16 % of them have masses over 38 g. What is the mean mass of the lizards, assuming that their masses are normally distributed? 4. Harshant measures the heights of 400 sixteen year old boys. The tallest is 191 cm tall and the shortest is 158 cm tall. Estimate the probability that a randomly selected sixteen year old boy is between 169 cm and 180 cm tall. What assumptions are needed for this estimate to be valid?
6 books lined up: When We Were Orphans, Bright Paradise, Precipice, The Playboy of the Western World, Karla's Choice and Twelve Bar Blues
Three sets of related functions with sad or smiley faces next to them. The functions are related by increasing factors of x.
Screenshot of a normal probability plot created using desmos (link in post)
XKCD cartoon with James Bond in a centrifuge.
A District Line notice about a defected [sic] train.
Weather forecast for Ealing showing rain.
Cover of the book The Heart in Winter by Kevin Barry.
A Casio fx-4000p calculator from the late 1980s
A white snowflake on a blue background. The polar equation of the snowflake is r = 16 + 6sin6θ + 4cos36θ
A set of 3D coordinate geometry questions, with the title in festive green and red font.
A cosine rule calculation with working from log tables.
The curve |x| + |y| + 2|xy| = 3 is shown in red. It's a four-pointed star, symmetrical in the x- and y-axes. Its interior is shaded green.
An instruction on a whiteboard: sketch y=sinx/(x-sinx)
The curve y=x² is in red. Two normals, at points in the second quadrant, intersect eachother at a point on the curve in the first quadrant with y-coordinate 3. The area enclosed by the curve and the two normals is shaded green.
The graphs of y = a/x³ and y = a - x³ are in red. They share a mutual tangent point in the first quadrant. The area enclosed by the x-axis and the two curves, with no upper limit, is shaded green.
A parabola passing through the origin and a positive value on the x-axis, with a maximum point in the first quadrant. A straight line with positive gradient intersects the parabola at 2 points in the first quadrant. Vertical line segments are drawn from each of these intersection points to the x-axis, so the area enclosed by the parabola and the x-axis is divided into 4 regions. The left hand region has area 13, the right hand region has area 44 and the top region has area 8. The final region is labelled with a question mark.
The graph of y=x² is in red, together with the point (sqrt3 / 2, 3/4) highlighted and labelled in blue. Also in red is a circle, tangent to the x-axis and touching the curve at the blue point. The region enclosed by the curve, the circle and the x-axis is shaded green.