(x-二分之一)的平方(x+二分之一)的平方-(x+四分之一)的平方
=[(x-1/2)(x+1/2)+(x+1/4)][(x-1/2)(x+1/2)-(x+1/4)]
=(x^2-1/4+x+1/4)(x^2-1/4-x-1/4)
=x(x+1)(x^2-x-1/2)平方呢？(x-1/2)^2(x+1/2)^2=[(x-1/2)(x+1/2)]^2令：(x-1/2)(x+1/2)=a(x+1/4)=ba^2-b^2=(a+b)(a-b)