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| Thread ID: 29820 | 2003-02-04 01:16:00 | OT: A question for skilled mathematicians, or am I just thick? | Billy T (70) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 118061 | 2003-02-04 01:16:00 | Hi Team I need a hand with a mathematical problem. I'm OK on most routine stuff but my maths education finished in in the 60's and this has me stumped. I have a series of formulae for calculating particular electrical characteristics at varying frequencies including some worked examples (minus the actual working unfortunately). The actual characteristics are unimportant, it is the means of obtaining the result that I can't fathom. The formulae include a decimal fraction i.e. 0.247 or 0.5 in superscript after the number in the same way that we might write a power. Problem is, I haven't the faintest idea how the superscript number is applied and even my fairly switched on daughter (who just passed fifth form NCEA maths while still a 4th former) can't help. All she can do is laugh at my struggles with all the sensitivity that we have come to expect from children when they finally realise that not only do their parents not know everything, sometimes they know nothing at all! :( Here are a few examples with the final result included. 3454f (0.753) = 1733 [where f= 0.4, and (0.753) follows f in superscript and without the curved brackets] 9.06/f (0.247) = 11.4 [where f = 0.4, with 0.247 as in the example above] The value f is the frequency in MHz and the examples given above are for a frequency of 400 kHz. A couple of example for a superscript factor of 0.5 are: 44f (0.5) = 2147 where f = 500MHz 0.118f (0.5) = 5.7 (f is again 500MHz) I want to solve the following examples for f = 350 kHz 3454f (0.753) =? 493f (0.753) =? 9.06/f (0.247) =? 4.13/f (0.247) =? Obviously the decimal fraction is a power or factor of some sort but I'm not even sure that description is correct. I'm picking that a scientific calculator is required for this and I have one right in front of me now, but the problem is I can't drive the thing apart from a few very basic functions. Any help will be gratefully accepted. Cheers Billy 8-{) Imagine emoticon for face full of hope here:......... Oh how I wish I'd paid more attention in maths all those years ago :( :( |
Billy T (70) | ||
| 118062 | 2003-02-04 01:25:00 | I wouldn't know either. I'm the village eejit | Horses Hoof (3080) | ||
| 118063 | 2003-02-04 01:34:00 | What are you calculating? The forms you give don't seem like anything I have seen. A superscript "0.5" means square root, "0.25" would be fourth root. There is often a factor of "2 pi f" in electronic calculations: that gives the "omega" term -- radians/sec . As in XC=1/omega.C, and XL=omega.L . Sometimes the "2 pi" is calculated ouit and given as 6.28(etc) or even as the reciprocal ... delay while he pulls out the slide rule ... approximately .16 . I don't know whether to be ?:| or :_| or :O |
Graham L (2) | ||
| 118064 | 2003-02-04 01:40:00 | Eeasy peasy japanese ok lets look at this equation 3454f^.753 where f= 0.4 The thing to remember is that you must work out f^.753 first so 0.4^.753 = 0.502 then times this by 3454 3454 x 0.502 = 1733 Now i don't want to solve them all for you, otherwise that would destroy the fun :-) |
roofus (483) | ||
| 118065 | 2003-02-04 01:43:00 | Fecken hell, where did you guys get your brains. Can I get one too | Horses Hoof (3080) | ||
| 118066 | 2003-02-04 01:45:00 | I feel better already Graham :) The formulae are taken directly from a New Zealand Standard, and the first complete example yield a field value of 1733 Volts per metre, and the second a field value of 11.4 Amperes per metre. The more I tried the confuseder I got :8} I might play with with the possible square root example and see what happens. Cheers Billy 8-{) :D |
Billy T (70) | ||
| 118067 | 2003-02-04 01:53:00 | The button your after is x^y in the case of the windows scientific calulator. or will be x with a superscript y above it. Those buttons let you do 'to the power of' |
-=JM=- (16) | ||
| 118068 | 2003-02-04 01:54:00 | Thanks Roofus, but what does the ^ represent? One or two clearly worked examples suitable for somebody who spent too much time asleep in maths classes would be a real help:8} Cheers Billy 8-{) :| |
Billy T (70) | ||
| 118069 | 2003-02-04 01:55:00 | > > The more I tried the confuseder I got :8} Interesting, you learn a new word every day :-) |
roofus (483) | ||
| 118070 | 2003-02-04 01:56:00 | > > The more I tried the confuseder I got :8} Interesting, you learn a new word every day :-) |
roofus (483) | ||
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