A truly incredible fact about the number 37

This is cool: A truly incredible fact about the number 37. I didn’t read it closely but 37 is my lucky number, so it held some interest. The conclusion is:

37, the median value for the second prime factor of an integer; thus the probability that the second prime factor of an integer chosen at random is smaller than 37 is approximately one half.

Math homework

I will let you in on a little secret: I love doing math homework. Always have, always will. I love the process. I love reading the problems, thinking of solutions, and checking the questions off one by one. Even when it’s easy, it’s still fun.

Just for fun I’ve gone back to my old high school math textbooks. I’m skipping years 7 and 8 and starting with year 9. Then I will do 10, 11, and 12, at the highest level.

At the moment I’m working through Australian Signpost Mathematics New South Wales 9 (5.1-5.3) Student Book, which is the year 9 textbook. I’m only up to page 10, fractions and ratios. I should work on it more than I do. Let’s see what I can do about that. :)

The most difficult math problem in this year’s HSC

The “HSC” in Australia is the “High School Certificate” which you get when you graduate high school. In order to do that you have to take the final exam, known as the “HSC exam”, or simply the “HSC”.

When I did the HSC 24 odd years ago the top level maths course (which I took) was called “4 Unit Maths”, whereas these days the top level course is now called “Maths Extension 2”. I expect the difficulty increased over the decades too.

Here’s the hardest question from this year’s Maths Extension 2 HSC paper:

There’s an article about it all in the newspaper today: ‘Not seen a question like it’: The most difficult problem in this year’s HSC.

I don’t remember enough about complex numbers, geometry, and trigonometry to answer this question, it is quite beyond me.

Early Content #6: Testing Riden RD6006 with 19.5V power supply | In The Lab With Jay Jay

This post is part of my video blog and you can find more information about this video on this show’s homepage which is here.

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Today I confirmed I can successfully power my Riden RD6006 power supply with this 19.5V AC adapter I picked up from Amazon. Big thanks to my mate Rick over on the EEVBlog forum for his help with this one.

In this video I use a 100W 6Ω resistor to test my Riden RD6006 power supply at various voltages from 1V to 18V up to a maximum power of 54W.

I should note that in this video I tried to draw 54W of power from the power supply, but the power supply is only rated up to 45W so I probably shouldn’t have done that, and won’t have any reason to ever do that again, I was just testing the maximum. So maybe don’t do that at home. :)

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CRC

I watched Ben Eater’s videos How do CRCs work? and Checksums and Hamming distance (the full course is Learn about error detection) then found the Wikipedia page: Cyclic redundancy check.

Also of interest: