1
00:00:00,430 --> 00:00:04,430
Jom kita cuba cth lain bagi Lokus.

2
00:00:05,108 --> 00:00:10,488
Diberi titik tetap A, B dan 
titik bergerak P;

3
00:00:15,718 --> 00:00:25,468
PA : PB = 2 : 1

4
00:00:26,732 --> 00:00:30,612
Jadi apakah cara utk dapatkan 
persamaan Lokus ini?

5
00:00:31,005 --> 00:00:33,525
Mudah saja.

6
00:00:33,707 --> 00:00:36,787
Tukarkan ke dlm bentuk pecahan.

7
00:00:36,916 --> 00:00:41,296
PA/PB = 2/1

8
00:00:46,721 --> 00:00:48,631
Darab silang persamaan ini.

9
00:00:48,888 --> 00:00:49,728
Kita akan dapat:

10
00:00:49,969 --> 00:00:54,769
PA = 2PB

11
00:01:00,758 --> 00:01:04,548
Gunakan formula jarak.

12
00:01:04,745 --> 00:01:13,275
PA: 
√ [ (x - 3)2 + (y-4)2]

13
00:01:14,200 --> 00:01:16,260
= 2PB,

14
00:01:20,538 --> 00:01:32,788
PB:
√ [ (x - 1)2 + (y - (-6))2]

15
00:01:37,627 --> 00:01:43,507
Ingat, kuasa-dua kan persamaan 
utk hapuskan √

16
00:01:43,584 --> 00:01:44,764
Hasilnya,

17
00:01:44,939 --> 00:02:08,089
(x - 3)2 + (y - 4)2 = 4 [ (x-1)2 + (y+6)2]

18
00:02:08,266 --> 00:02:09,226
Kemudian, kembangkan persamaan ini.

19
00:02:09,393 --> 00:02:33,523
x2 - 6x + 9 + y2 - 8y + 16 = 
4 [ x2 - 2x + 1 + y2 + 12y + 36]

20
00:02:33,681 --> 00:02:34,711
Kembangkan lagi PB:

21
00:02:35,018 --> 00:02:48,508
4x2 - 8x + 4 + 4y2 + 48y + 144,

22
00:02:48,718 --> 00:02:58,278
Dan PA:
x2 - 6x + y2 - 8y + 25

23
00:03:01,487 --> 00:03:05,487
Kumpulkan semua nilai di sebelah kanan (PB).

24
00:03:07,712 --> 00:04:03,242
3x2 - 2x + 3y2 + 56y + 4 + 144 - 25 = 0

25
00:04:03,640 --> 00:04:05,200
Susun dan ringkaskan.

26
00:04:05,474 --> 00:04:18,264
0 = 3x2 + 3y2 - 2x + 56y + 123

27
00:04:18,738 --> 00:04:22,738
Inilah persamaan Lokus yg kita cari.