HP-35S 'Guide for Dummies' being posted online
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05-03-2015, 11:12 AM
Post: #32
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RE: HP-35S 'Guide for Dummies' being posted online
From 3. Introduction to RPN:
Quote:You discover the way to convert °F to °C is: You start with writing the numbers on the whiteboard: 9 5 72 32 But why did you chose this order? Why are 5 and 9 swapped? Most probably because otherwise you'd have to use [x<>y] twice: 5 9 72 32 - x<>y / x<>y * Given this example there are two possibilities I would calculate it. Outside in: 5 9 / 72 32 - * This is basically how a computer translates the algebraic expression to RPN: Code: echo "(5 / 9)*(72 - 32)" | bc -c Inside out: 72 32 - 5 9 / * In both cases there's no need to swap any values. Quote:For good measure, let’s try the built-in calculator °F to °C function From a pedagogical point of view this devaluates your introduction to RPN. Why do something in a complicated way when there's a dedicated key for it? Recommendation: You propose to push all the numbers first and only then start with the calculations. But this won't work with more than 4 numbers. Instead you should explain why and when an intermediate result is kept on the stack for later use. Given that there's a built-in function I think that this is a bad example. I'd probably use a grocery store problem like calculating the total of buying the multiple items you need for a cake. Kind regards Thomas |
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