(1-t)²+4t²/(1+t)²=(1+t²)/(1+t)这是怎么化简的
(1-t)²+4t²/(1+t)²
=[(1-t)²(1+t)²+4t²]/(1+t)² 通分合并
=[(1²-t²)²+4t²]/(1+t)²
=(1-2t²+t^4+4t²]/(1+t)²
=(1+2t²+t^4]/(1+t)²
=(1+t²)²/(1+t)²
化不成(1-t)²+4t²/(1+t)²=(1+t²)/(1+t)的形式
√[(1-t)²+4t²/(1+t)²]=(1+t²)/(1+t)是成立