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Originally posted by RK
right, ok lets try something a little harder:
find the error:
-2 = -2
4 - 6 = 1 - 3
4 - 6 + 9/4 = 1 - 3 + 9/4
(2 - 3/2)^2 = (1 - 3/2)^2
2 - 3/2 = 1 - 3/2
2 = 1
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The error is in assuming that, if a^2 = b^2, then a=b
Actually, if a^2 = b^2, all you can say is that |a| = |b|, where |a| means the module of a, i.e., a without a sign
(2-3/2)^2=(1-3/2)^2 =>
(2-3/3) = (1-3/2) is WRONG
(2-3/2)^2=(1-3/2)^2 =>
|2-3/2| = |1-3/2| =>
|1/2| = |-1/2| = 1/2 is OK
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