看板
[ Math ]
討論串[中學] 高中數學一題
共 12 篇文章
內容預覽:
2.. we have (bc+ca+ab)(a+b+c) = abc. consider x^3 + px^2 +qx +r = 0. with x = a, b, c. x^3 +px^2 +qx +pq = 0 {note that p,q =! 0}. = (x^3 +qx) + p(x^2
(還有74個字)
內容預覽:
1.. proof ax+by=c exist Z solution, then (a,b)=k|c. if (a,b)=k then a=ka', b=kb', (a', b')=1. ax+by = ka'x +kb'y =k(a'x+b'y)=c. if (x,y) exist Z solut
(還有282個字)
內容預覽:
令t=x^2. 則原式=t^2+(m-5)t+(m+3)有兩個相異正根. 故判別式=(m-5)^2-4(m+3)=m^2-10m+25-4m-12=m^2-14m+13>0. => (m-13)(m-1)>0 => m>13 or m<1 ...(1). 兩根和=-(m-5)=5-m>0 => m<
(還有54個字)