已知a=1/2m+1,b=1/2m+2,c=1/2m+3,求a^2+2ab+b^2-2ac+c^2-2bc的值.
问题描述:
已知a=1/2m+1,b=1/2m+2,c=1/2m+3,求a^2+2ab+b^2-2ac+c^2-2bc的值.
兄弟,
答
a^2+2ab+b^2-2ac+c^2-2bc
=(a+b-c)^2
=(1/2m+1+1/2m+2-1/2m-3)^2
=(1/2m)^2
=1/(4*m^2)