设 a = √2 ,b = √3 ,c = √58+2√15-√10-√6 = 8 + 2bc - ac - ab= bb + cc + bc + bc - ac - ab （注意8 = √3×√3 + √5×√5） = (bb + bc - ab) + (cc + bc - ac)= b×(c + b - a) + c×(c + b - a)= (b + c...