Any mathematicians on here?

[Blaketon]

I am trying to work out how the equation, at the bottom of page 69, becomes the solution on page 70. It is a long time since I did O level maths but I don't recall anything quite like this, so maybe this would be A level or perhaps higher again?

As I read it, you have P X what is in the square bracket, which includes the sum within the () bracket, which is equal to 0.002" divided by 2. I also read that E1 = 30 X 10 to the power of 6 or 30 000 000 and that E = 10 X 10 to the power of 6 or 10 000 000. I must be reading it wrong, as I certainly don't get the answer they do. Working out the final sum, as printed on page 70, I get 7377, which they have presumably rounded up to 7400.

It's from a book about engineering tolerances, something I have either been given (To work to) or just done, based on experience. Oddly enough, I met the author once or twice but he's been dead for about 35 years, so I can't ask him!!

[Bill_qaz]

0.001 x 7.3770491803 x 1000000 = 7377.0491803279
Rounded to 7400 lbs/sq.inch

[Blaketon]

I just can't make out where they got the figures from, to make the calculation .

[philthehill]

If it wont fit get a bigger hammer

[Bill_qaz]

I just can't make out where they got the figures from, to make the calculation .

As I explained:
0.002 ÷ 2 = 0.001
900 ÷ 122 = 7.377
0.001 x 7.377 = 0.007377
Multiply by 10 to power of six 1000000
= 7377 they have rounded to 7400
That's as close as I get

Or do you mean where those numbers come from in the calculation?

[Blaketon]

Yes it's the numbers, which appear to be fed into the last equation on page 69. So far as I know, p, placed in front of the square bracket, means that the contents of the bracket are multiplied by p. Within the square bracket, the figures in the regular brackets are worked out , multiplied by 1 /E1 and added to 7/10E. That apparently equals interference / 2|R1. Based on my assumptions, I was nowhere near, so I must have assumed wrong.

[Blaketon]

If it wont fit get a bigger hammer

Just don't go beyond the elastic limit or it could break or lose interference .

[Bill_qaz]

Yes it's the numbers, which appear to be fed into the last equation on page 69. So far as I know, p, placed in front of the square bracket, means that the contents of the bracket are multiplied by p. Within the square bracket, the figures in the regular brackets are worked out , multiplied by 1 /E1 and added to 7/10E. That apparently equals interference / 2|R1. Based on my assumptions, I was nowhere near, so I must have assumed wrong.

What values are you entering into the equation

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[Blaketon]

Best if I attach my scribblings.......give everyone a laugh .

Also, a few pages further along, there are sums with dots between the numbers and I don't know what they represent?

[Bill_qaz]

I don't know how many posts before we are banned

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[Blaketon]

How on earth do they get the figures on page 70

[Bill_qaz]

Your a step up on me with your O level maths, I left school 56 years ago with none