wij
2024-01-14 13:05:45 UTC
Assume we can make a ruler to measure length M to any desired precision p, M+10^(-p),p∈ℕ.
So, the readout of the measure is in range [M-10^(-p), M+10^(-p)]
Ex1: Let M=1
0.9 <= 1 <= 1.1
0.99 <= 1 <= 1.01
0.999 <= 1 <= 1.001
...
Finally: 1 <= 1 <= 1 (according to Squeeze Theorem)
Corollary: Infinite long decimal does not denote a number, such a number
does not exist.
Ex2: Let M=√2 (the diagonal of unit square)
1.4 <= √2 <= 1.5
1.41 <= √2 <= 1.42
1.414 <= √2 <= 1.415
...
Finally: √2 <= √2 <= √2 (according to Squeeze Theorem)
Conclusion: √2 can be exactly measure by a ruler (we can make p close to 0
to any degree we want except p≠0)
Corollary: √2(and π) is a ration number (decimal cannot be infinitely long, no such number exists)
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Don't complain, this is your math !!!
So, the readout of the measure is in range [M-10^(-p), M+10^(-p)]
Ex1: Let M=1
0.9 <= 1 <= 1.1
0.99 <= 1 <= 1.01
0.999 <= 1 <= 1.001
...
Finally: 1 <= 1 <= 1 (according to Squeeze Theorem)
Corollary: Infinite long decimal does not denote a number, such a number
does not exist.
Ex2: Let M=√2 (the diagonal of unit square)
1.4 <= √2 <= 1.5
1.41 <= √2 <= 1.42
1.414 <= √2 <= 1.415
...
Finally: √2 <= √2 <= √2 (according to Squeeze Theorem)
Conclusion: √2 can be exactly measure by a ruler (we can make p close to 0
to any degree we want except p≠0)
Corollary: √2(and π) is a ration number (decimal cannot be infinitely long, no such number exists)
---------------------------------------------
Don't complain, this is your math !!!