Re: HP35 Ad. from 1972 with calculation error reused in 2009? Message #18 Posted by Thomas Klemm on 10 May 2013, 2:40 p.m., in response to message #14 by Michael Kathke
You could avoid cancellation using the identity:
You would end up with:
a) 2,5 / 10,3 = (D)/(C) -> (1D) = 0,243
b) 0,243ˆ2 = (D)->(A) = 0,059
c) 0,059 + 1 = 1,059
...
SQR(1,059) = 1,029
Pi * 0,059 = 0,185
0.185 * 2 = 0,37
0,37 / 1,029 = 0,36
0,36 / 2,029 = 0,177
However I didn't use a slide rule but the results might be close enough.
This formula might be even easier to use:
a) 2,5 / 10,3 = (D)/(C) -> (1D) = 0,243
b) 0,243ˆ2 = (D)->(A) = 0,059
c) 0,059 + 1 = 1,059
...
SQR(1,059) = 1,029
Pi * 0,059 = 0,185
0.185 * 2 = 0,37
1 + 0,059 + 1,029 = 2,088
0,37 / 2,088 = 0,177
Kind regards
Thomas
Edited: 10 May 2013, 3:03 p.m.
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