1.x^2-4x+1=0 推出 x^2=4x-1;
2.所以x^2-1/(x^2)=(4x-1)-1/(4x-1)=(16x^2-4x-1)/(4x-1)-1
=(16*(4x-1)-4x-1)/(4x-1)-1=(60x-15)/(4x-1)-1=15*(4x-1)/(4x-1)-1=15-1=14
若x的平方减4x加1=0,求x的平方减x的平方分之一的值
1.x^2-4x+1=0 推出 x^2=4x-1;
2.所以x^2-1/(x^2)=(4x-1)-1/(4x-1)=(16x^2-4x-1)/(4x-1)-1
=(16*(4x-1)-4x-1)/(4x-1)-1=(60x-15)/(4x-1)-1=15*(4x-1)/(4x-1)-1=15-1=14