數學問題1條(須列式)

L:y=mx 4
mx-y 4=0

a.

L1〃L
∴Slope of L1 = Slope of L
-(2m+1) = m
-2m-1 = m
3m = -1
∴m = -1/3



b.

L2⊥L
∴Slope of L2 x Slope of L = -1
-[1/(3m+1)] x m = -1
-[m/(3m+1)] = -1
-m = -3m-1
2m = -1
∴m = -1/2

2008-10-08 23:15:14 補充：
y=mx+4
mx-y+4=0
∴m=A, -1=B, 4=C


因為Slope = -(A/B)
∴Slope of L =-(m/-1) = m

L1同L2既Slope都係咁搵！

其餘我剛剛上堂學完，F.5數黎波呢條！

y= mx 4,
L1:(2m 1)x y=0
L2: x (3m 1)y-4=0

Slope of L1=-(2m 1)=m
m=-1/3

L2: x (3m 1)y-4=0
y=(-x 4)/(3m 1)
m*-1/(3m 1)=-1
m=-1/2