Easy way to remember sin, cos and tan values

One of my tutees showed me an easy way to remember sin and cos values for the “common” angles, and once you’ve got those you’ve also got tan, cosec, sec and cot. Continue reading

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Correlation between Astronaut name and Apollo mission

Perhaps we’ve finally worked out Deke Slayton’s method for choosing the Apollo crews, basing it on alphabetical order… Continue reading

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Rooney Scores 50 goals for England – the data

So Wayne Rooney (I assume in the future it will be Sir Wayne) has broken the England goal scoring record with 50 goals. A lot of discussion has therefore been about if he is the greatest English attacker of all time or not. Let’s look at the data. Continue reading

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Safe Reboot of Locked Linux Machine

Sometimes your Linux machine will lock up, it just happens. But before you reach for the reset button try and use the magic SysRq key combination to try and perform a safe reboot. Continue reading

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Quick way to remove X Server for running a headless server

I use my Raspberry Pi as a headless server so do not need anything that relies on X11, this is a quick way to get rid of everything that depends on X11 to save some space. Continue reading

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How far is 1 astronomical unit (AU)?

An astronomical unit (AU) is a commonly used unit in astronomy, but what exactly is its value?

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Making files and folders lowercase

Very occasionally I want to make all the files and folders of a particular directory lowercase (usually when porting an existing directory structure from Windows to Linux) this is how I do it.  Continue reading

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Math(s) can be confusing…

I meet a man walking down the street, who I know has two children. He introduces me to his son, what is the probability that his other child is a girl? Continue reading

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Goodbye Google Reader

As we say goodbye to one of my favourite Google features it is time to find a replacement.     Continue reading

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Standard Deviation in IDL

The built in IDL standard deviation function in IDL, STDDEV, uses the moment function which treats the standard deviation as a sample, rather than a population. A short programme can give us both options.  Continue reading

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