F.4 MATHS

As follows:

圖片參考：http://i707.photobucket.com/albums/ww74/stevieg90/07-32.jpg


2010-07-17 19:05:44 補充：
Explanation on part (c):
http://i707.photobucket.com/albums/ww74/stevieg90/15-9.jpg

1. Slope of L1 = sqrt 3
Slope of L2 = (2 sqrt 3)/2 = sqrt 3.
So L1//L2 since their slopes are the same.
2. Slope of L2 = sqrt 3
Put y = 0 into equation of L2
2 sqrt 3 x - 2(0) + 5 = 0
x = -5/(2 sqrt 3) = x - intercept.
3. Let angle between L2 and the x - axis = a
so tan a = slope of L2 = sqrt 3 ( so a = arctan sqrt 3 = 60 degree.)
(Distance between L1 and L2 )/(x - intercept of L2) = sin 60
so distance between L1 and L2 = sin 60 ( x - intercept)
= (sqrt 3)/2 x 5/ (2 sqrt 3) = 15.