土木建築專業交流、技師證照、職場就業、軟體技巧交流的好所在。https://www.civilgroup.org/
https://www.civilgroup.org/viewtopic.php?f=15&t=16716
NBA 寫:Y = X1 + 2*X2 + X3 = 750cm偏微分YmY = ±[(1^2)*(2^2) + (2^2)*(3^2) + (1^2)*(4^2)]^(1/2) = ±7.48cm