x^2-√2x-1/4=0

来源:百度知道 编辑:UC知道 时间:2024/05/17 03:22:50
急急急。配方解答

x^2-√2x-1/4=0
x^2-2*(√2/2)x-1/4=0
x^2-2*(√2/2)x+(√2/2)^2-(√2/2)^2-1/4=0
[x-(√2/2)]^2=3/4
[x-(√2/2)]^2=(√3/2)^2
x-(√2/2)=√3/2或-√3/2
所以x1=(√3+√2)/2,x2=(√2-√3)/2

原式=(x-√2/2)^2-3/4
=(x-√2/2+√3/2)(x-√2/2-√3/2)

(x^2-√2/2)^2=3/4

x^2-√2x-1/4=0
x^2-√2x+1/2=1/4+1/2
(x-√2/2)^2=3/4
x-√2/2=±√3/2
x=(√2±√3)/2