Re: [代數] 資優班考題1題
※ 引述《stu2005131 (自由幻夢)》之銘言:
: 解方程式[5-(5-x)^(2)]^2=x
令t=5-x =>x=5-t≧0=>5≧t
=> (5-t^2)^2=5-t
=> 25-10t^2+t^4=5-t
=> t^4-10t^2+t+20=0
=> (t^2+t-5)(t^2-t-4)=0
=> t=-1±√21/2 or t=1±√17/2
=> x=11±√21/2 or x=9±√17/2
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 111.252.213.233
推
08/05 20:43, , 1F
08/05 20:43, 1F
→
08/05 20:43, , 2F
08/05 20:43, 2F
推
08/05 21:48, , 3F
08/05 21:48, 3F
討論串 (同標題文章)