Question

1/[(2^-2)+1]为什么等于2(2^-2)-1

请写出流程

Answer 1

化简
√（1+k^2）[(x1-x2）^2 ]
设y=kx十b
y1-y2=k(x1-x2)
线段长= √[(x1-x2)²十(y1-y2)²]
= √[ (x1-x2)²十 k²(x1-x2)²]
= √[(1十k²)(x1-x2)²]
= √{(1十k²)[(x1十x2)²-4x1x2]}