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John Rubinstein

@jrub.bsky.social

460 followers 520 following 310 posts

Teacher of A level maths and further maths. Ex-principal of a sixth form college. Now a Londoner but still loyal to Hull.

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John Rubinstein @jrub.bsky.social · 2d

Haha, nice distinction

John Rubinstein @jrub.bsky.social · 2d

I gave my Y12 students a test today in #ALevelMaths . They complained afterwards that they didn’t know what a rhombus is.
I don’t teach GCSE: would you not expect students to know what a rhombus is at GCSE?

John Rubinstein @jrub.bsky.social · 9d

Don’t you hate it when a student asks for help with part (iv) of a STEP question?

John Rubinstein @jrub.bsky.social · 10d

I recommend this movie. Thrilling and funny and entertaining. And incredible soundtrack.

John Rubinstein @jrub.bsky.social · 13d

Wow!

John Rubinstein @jrub.bsky.social · 13d

I taught both methods last year. Every single student preferred the parallel/perpendicular vector method. Maybe it was because I taught that first, but I think the main reason is that method makes sense, it is visual and transparent.

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John Rubinstein @jrub.bsky.social · 16d

Field trip to Hurn?

John Rubinstein @jrub.bsky.social · 24d

Is it just me or was #OnlyConnect easier tonight?

John Rubinstein @jrub.bsky.social · 25d

If you have the initial and final velocities in vector form, then you can find the angle of deflection using the scalar product

John Rubinstein @jrub.bsky.social · 27d

Thank you. Should have checked that document first!

John Rubinstein @jrub.bsky.social · 27d

Wow, that’s clever!

John Rubinstein @jrub.bsky.social · 27d

Definitely agree re the mark allocation. I just looked up what the E means and you’re right. Damn, I have been telling student for 4 years that they are past paper questions!

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John Rubinstein @jrub.bsky.social · 27d

It’s marked as a past paper question. In an exam I would be trying to solve the equations analytically not just spot a solution. And I don’t think they would be expecting us to solve a polynomial of degree 6 by using the factor theorem with trial and error.
I think I must be missing something.

John Rubinstein @jrub.bsky.social · 28d

How is this a past paper question?

John Rubinstein @jrub.bsky.social · 28d

I am stuck if any kind soul can help. In the Edexcel Core 1 chapter on roots of polynomials Ex4C Q9, you end up with these four equations, which I haven’t been able to solve.
Solution bank just ‘spots’ the solution, which isn’t very satisfactory.
#ALevelMaths

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John Rubinstein @jrub.bsky.social · 28d

Fair enough

John Rubinstein @jrub.bsky.social · 28d

As it happens, we did that today. We discussed afterwards whether it was easier to take a out as a factor or divide through by a. We decided better to divide through.

John Rubinstein @jrub.bsky.social · 29d

If you are at all interested in WW2, in what Britain was like in the late 30s and during the war, in debunking some myths and learning some history, I wholeheartedly recommend this book.

John Rubinstein @jrub.bsky.social · Aug 31

I’m old school: I mark it properly/fully and give them a numerical mark. I go over common issues with the class as a whole and go over individual issues with students 1-1. Sometimes I give a mark 2 homework to those who scored poorly.

John Rubinstein @jrub.bsky.social · Aug 29

Good.

John Rubinstein @jrub.bsky.social · Aug 29

When I was principal of a SFC there were tons of services we couldn’t access, lots of information/data we weren’t entitled to, loads of funding streams we couldn’t apply for. When we academised, that changed.

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John Rubinstein @jrub.bsky.social · Aug 29

I’m not sure sixth form colleges can access that service, I think it might be just schools. But I hope I’m wrong.

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John Rubinstein @jrub.bsky.social · Aug 29

Been on the beach four days in the last seven. Seen quite a few women reading books but only one man (and that was Jeffrey Archer so not sure if it counts).

John Rubinstein @jrub.bsky.social · Aug 26

Lots of pleasing mathematical spirals in these plants in a garden in Cornwall.

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John Rubinstein @jrub.bsky.social · Aug 24

The novel is excellent.