关于乘法公式的算式题,

=（1-x^2/4)(1+x^2/4)(1+x^4/16)==（1-x^4/16)(1+x^4/16)=1-x^8/256
=-（y-2x)(2x+y)=(2x-y)(2x+y)=4x^2-y^2
=1000*1002-2*1002-1000*1001+1001=1000*(1002-1001)+1001-2*1002=1000+1001-2004=-3
=(100-99)(100+99)+(98-97)(98+97).(2-1)(2+1)=199+195+...+3=(199+3)*50/2=5050
=(1-1/2)(1+1/2)(1-1/3)(1+1/3)...(1-1/10)(1+1/10)=1/2*3/2*2/3*4/3*3/4*5/4*...*9/10*11/10=11/20
=（3-1)(3+1)(3^2+1)(3^4+1)(3^8+1)/2-3^16/2=(3^16-1)/2-3^16/2=-1/2