化简:|a-c|-|c-d|-|b-a|+2|a+b| ------c----a--0-----------------
[a,b)×[c,d
a,b ,c ,d
a,b,c,d>0 证(a/(b+2c+3d))+(b/(c+2d+3a))+(c/d+2a+3b))+(d/(a+2b
已知a《b《0《c,化简|a-b|+|a+b|-|c-a|+2|c-b|.
A>B,C>D.A+C
b/a(a+b)+c/(a+b)(a+b+c)+d/(a+b+c)(a+b+c+d)
化简:2a-b-c/(a-b)(a-c) + 2b-a-c/(b-c)(b-a) + 2c-a-b/(c-b)(c-a)
化简(2a-b-c)/(a+b)(a-c)+(2b-c-a)/(b-c)(b-a)+(2c-a-b)/(c-b)(c-a
求证(b,c,d)a+(c,a,d)b+(a,b,d)c+(b,a,c)d=0 a,b,c,d皆为向量>
( )-(c-d)=(a-c)-(-b+d)
化简:(2a-b-c)/(a-b)(a-c)+(2b-c-a)/(b-c)(b-a)+(2c-a-b)/(c-a)(c-
化简:a+b/(a-c)(b-c)-b+c/(a-b)(c-a)+c+a/(c-b)(a-b)