ChaseDream

标题: 明天考，急问JJ一道！MATH [打印本页]

作者: danielfeiwan 时间: 2006-9-27 13:02
标题: 明天考，急问JJ一道！MATH

19、已知，a=x+1/x,b=x-1/x，求2^（a^2）/2(b^2) 实际上知道a^2-b^2=4就行了，

答案16

a^2-b^2明明等于X分之4吗？

作者: systemunknow 时间: 2006-9-27 13:08

Please read JJ 19

goes like (x+1/x)(x+1x) - (x-1/x)(x-1/x) then do the whole muti .. you'll get 4 and 2^4 = 16.... that's the NONE NN way of doing it... so you can get the answer, just take a little time..

欢迎光临 ChaseDream (https://forum.chasedream.com/)