Question

13．1-$\sqrt{2}$絕對(duì)值是$\sqrt{2}$-1，相反數(shù)是$\sqrt{2}$-1，倒數(shù)是-1-$\sqrt{2}$．

Answer 1

分析 根據(jù)差的絕對(duì)值是大數(shù)減小數(shù)，只有符號(hào)不同的兩個(gè)數(shù)互為相反數(shù)，乘積為1的兩個(gè)數(shù)互為倒數(shù)，可得答案．

解答 解：1-$\sqrt{2}$絕對(duì)值是 $\sqrt{2}$-1，相反數(shù)是 $\sqrt{2}$-1，倒數(shù)是-1-$\sqrt{2}$，
故答案為：$\sqrt{2}$-1，$\sqrt{2}$-1，-$\sqrt{2}$-1．

點(diǎn)評(píng) 本題考查了實(shí)數(shù)的性質(zhì)，利用差的絕對(duì)值是大數(shù)減小數(shù)是解題關(guān)鍵，求倒數(shù)時(shí)要分母有理化．