Jim Simons
@pippinsboss.bsky.social
Mathematician, tutor of A level maths, bridge player, father, grandfather and dog lover.
Maker of mathematical videos, mostly at the level of A levels
youtube.com/channel/UCnYszOhEIIdIMYyNx2yjwfg
Maker of mathematical videos, mostly at the level of A levels
youtube.com/channel/UCnYszOhEIIdIMYyNx2yjwfg
@davidkbutler.bsky.social It is a magnificent Autumn for berries here in the UK. Just look at this spindle bush in a field near my home.
September 19, 2025 at 9:45 AM
@davidkbutler.bsky.social It is a magnificent Autumn for berries here in the UK. Just look at this spindle bush in a field near my home.
That was a close game!
July 30, 2025 at 9:37 AM
That was a close game!
I suspect most pea plants are simply connected. Not this one. Cue other mathematically interesting plant pics.
July 18, 2025 at 9:22 AM
I suspect most pea plants are simply connected. Not this one. Cue other mathematically interesting plant pics.
This supermarket trolley wheel misunderstood the instructions concerning which axis it is supposed to rotate about.
July 4, 2025 at 11:55 AM
This supermarket trolley wheel misunderstood the instructions concerning which axis it is supposed to rotate about.
Pray tell me, Dr Fermi, how many flowers do you think there are on my wisteria.
April 23, 2025 at 12:45 PM
Pray tell me, Dr Fermi, how many flowers do you think there are on my wisteria.
Granddaughter has always loved rainbows. We made a rainbow-themed picnic for her 12th birthday. Note the black things at the end. They represent ultraviolet!
April 14, 2025 at 7:51 AM
Granddaughter has always loved rainbows. We made a rainbow-themed picnic for her 12th birthday. Note the black things at the end. They represent ultraviolet!
Our fritillaries are very happy by the pond.
April 5, 2025 at 9:14 AM
Our fritillaries are very happy by the pond.
Mathematics in School in shreds. Does anyone want a dog?
March 14, 2025 at 3:10 PM
Mathematics in School in shreds. Does anyone want a dog?
Looks like I forgot to attach the photo
February 27, 2025 at 5:28 PM
Looks like I forgot to attach the photo
Now, every point (a,b) on the plane lies on exactly one of these curves, namely the one where λ=f(a,b). So the curves cover the plane, and can do so very prettily. Here's a simple one for a hyperbolas x^2-xy-y^2=λ.
February 25, 2025 at 12:40 PM
Now, every point (a,b) on the plane lies on exactly one of these curves, namely the one where λ=f(a,b). So the curves cover the plane, and can do so very prettily. Here's a simple one for a hyperbolas x^2-xy-y^2=λ.
#MathsOnHoliday I'm rather enjoying watching this rotating door. Its circumference has 2 closed thirds and 2 open sixths so there can bo no draughts, (it is windy here). Also it has IR sensors, so stops if no-one wants to go through. Simple pleasures. Oh, and the breakfast is excellent!
February 18, 2025 at 9:49 AM
#MathsOnHoliday I'm rather enjoying watching this rotating door. Its circumference has 2 closed thirds and 2 open sixths so there can bo no draughts, (it is windy here). Also it has IR sensors, so stops if no-one wants to go through. Simple pleasures. Oh, and the breakfast is excellent!
Yes that's pretty, but surely we have introduced angles bigger than 90˚ by the time we want the addition formula, so what's with a proof that only works when 0<α<α+β<90˚? I move to defns based on the unit circle, and then a proof of cosine addition is simple, and the others follow.
February 9, 2025 at 10:02 AM
Yes that's pretty, but surely we have introduced angles bigger than 90˚ by the time we want the addition formula, so what's with a proof that only works when 0<α<α+β<90˚? I move to defns based on the unit circle, and then a proof of cosine addition is simple, and the others follow.
What is the oldest consumable in your household? I bought this tub of grease about 59 years ago. I don't use it often but used a little yesterday morning. Should last a few more years.
February 5, 2025 at 3:52 PM
What is the oldest consumable in your household? I bought this tub of grease about 59 years ago. I don't use it often but used a little yesterday morning. Should last a few more years.
Good Q. I get this, may not be right: the x co-ord is half the angle of the slice. For x<π/2 it's 1+cos(x) with the rectangle oriented with one side across the mouth of the slice. For π/2<x<3π/4, width is 1. For x>3π/4 the orientation switches so that one side is one of the radii of the slice.
December 27, 2024 at 4:31 PM
Good Q. I get this, may not be right: the x co-ord is half the angle of the slice. For x<π/2 it's 1+cos(x) with the rectangle oriented with one side across the mouth of the slice. For π/2<x<3π/4, width is 1. For x>3π/4 the orientation switches so that one side is one of the radii of the slice.
The greengrocer's apostrophe has a different meaning in Spanish.
October 27, 2024 at 3:38 PM
The greengrocer's apostrophe has a different meaning in Spanish.
In fact here it is
September 26, 2024 at 7:23 AM
In fact here it is
This is the simplest case. To show that if a body with a pivot is in equilibrium, the sum of the moments of the external forces is 0. I did it on the board with a lot more spoken words: I hope this is sufficient.
September 25, 2024 at 9:17 PM
This is the simplest case. To show that if a body with a pivot is in equilibrium, the sum of the moments of the external forces is 0. I did it on the board with a lot more spoken words: I hope this is sufficient.
Bluesky now has over 10 million users, and I was #6,179,921!
Turns out I'm a chameleon:
Turns out I'm a chameleon:
September 20, 2024 at 2:04 PM
Bluesky now has over 10 million users, and I was #6,179,921!
Turns out I'm a chameleon:
Turns out I'm a chameleon:
Talking of human pyramids, you might be amused by this slide from a talk I shall be giving:
September 12, 2024 at 8:18 AM
Talking of human pyramids, you might be amused by this slide from a talk I shall be giving: