|
Find real number x such that x+2 = x
Method 0 For any real number x, we know x+2 > x. Therefore it has no solutions. Method 1 (反证法) Suppose that it has a solution, i.e. there exists an x, such that x = x+2 => 0=2 Contradiction. so It has no solution. Meyjod 2 (反证法)
Suppose it has a solution, i.e., there exists an x, such that x = x+2 (1) => x^2 = (x+2)^2 => x=-1 代入(1) => -1=1 Contradiction. So it has no solution.
Archiver|手机版|科学网 ( 京ICP备07017567号-12 )
GMT+8, 2025-9-13 03:53
Powered by ScienceNet.cn
Copyright © 2007- 中国科学报社