F.4 數學 - 二次方程 (高手請進)

If the equation has repeated roots, discriminant = 0
Discriminant = (-18)^2 - 4(k)(2k) = 0
324 - 8k^2 = 0
324 = 8k^2
81/2 = k^2
k = 9/√2

Discriminant = 0

(-18)^2 - 4(k)(2k)= 0
(18)^2 - 8k^2= 0
324= 8k^2
2 (sq. root)2k= + / -18
k=9/ (sq. root) 2 or -9/ (sq. root) 2

希望可以幫到你

coz有一個二重實根
so delta=0
so (-18)^2-4(k)(2)=0
324-8k=0
-8k=-324
k = 81/2

2007-10-29 22:36:24 補充：
aiya中間打錯野係 so (-18)^2-4(k)(2k)=0 324-8k^2 = 0 -8k^2 = -324 k^2 = 81/2 k= 9/√2 or k= -9/√2 coz要開方所以會正副( /-)so2個answer