✨ 最佳解答 ✨
(2005 + 2005/2006)^2 = 2006^2 - a
a = 2006^2 - (2005 + 2005/2006)^2
= [2006 + (2005 + 2005/2006)][2006 - (2005 + 2005/2006)]
= (4011 + 2005/2006)(1 - 2005/2006)
= (4011 + 2005/2006)(1/2006)
= 4011/2006 + 2005/(2006^2)
(因為2005/(2006^2)遠小於1 所以可忽略)
≈ 2
1 - 2005/2006
= 2006/2006 - 2005/2006
= (2006-2005)/2006
= 1/2006
謝謝~
抱歉為甚麼
(4011 + 2005/2006)(1 - 2005/2006)
= (4011 + 2005/2006)(1/2006)