CHO TAM GIÁC ABC CÓ BC = A, CA = B, AB = C. NẾU A, B, C THEO THỨ TỰ L...
Câu 50:
Cho tam giác ABC có BC = a, CA = b, AB = c. Nếu a, b, c theo thứ tự lập thành một cấp số nhân thì
A.
ln sin A.ln sin C
2ln sin B
B.
ln sin A ln sin C
2ln sin B
C.
ln sin A.ln sin C
ln sin B
2
D.
ln sin A ln sin C
ln 2sin B
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STT 101
239
353
477
593
615
737
859
971
193
275
397
1
C
A
C
B
D
C
D
B
A
B
C
A
2
C
B
A
D
B
A
D
B
A
B
C
D
3
A
C
C
A
C
B
C
B
D
D
D
A
4
C
D
D
A
A
A
C
A
B
C
B
B
5
A
C
A
A
A
B
A
D
C
B
C
D
6
A
B
A
A
D
A
C
A
C
D
D
A
7
C
A
B
C
D
D
C
C
D
A
C
B
8
C
D
C
D
B
C
B
C
D
D
A
D
9
D
A
D
B
C
D
A
D
D
B
A
D
10
D
A
B
B
D
B
B
B
D
A
C
B
11
A
C
C
C
B
C
D
C
C
A
D
B
12
B
C
A
B
D
B
C
C
C
C
D
C
13
D
A
D
B
B
C
A
C
B
C
A
A
14
B
A
C
B
C
B
D
B
B
A
D
C
15
C
C
C
D
A
C
C
C
C
D
C
B
16
A
D
D
C
B
A
C
A
B
A
B
B
17
D
B
C
B
A
A
B
D
A
D
C
C
18
B
B
A
D
C
C
B
D
A
D
B
D
19
C
A
D
A
A
D
C
D
D
A
D
B
20
C
B
C
A
C
B
B
D
C
C
C
D
21
B
A
A
B
A
C
C
D
B
C
B
A
22
D
C
C
C
A
B
A
B
B
A
D
B
23
A
D
B
C
B
D
D
A
B
A
A
C
24
B
C
D
B
A
D
D
A
A
A
C
C
25
C
B
C
A
C
D
B
A
B
C
A
B
26
B
C
A
D
B
A
D
D
A
B
A
C
27
B
B
C
D
A
A
A
A
B
B
B
A
28
B
C
C
A
D
A
D
B
A
A
B
C
29
C
D
B
B
C
D
A
A
B
C
B
A
30
D
D
D
A
C
B
A
D
C
B
A
D
31
D
B
B
C
A
A
B
B
D
B
D
A
32
A
B
A
B
A
C
B
C
D
D
A
C
33
D
A
B
A
B
D
A
A
D
C
C
B
34
D
B
A
B
D
C
C
B
B
D
A
D
35
B
A
D
D
C
C
B
B
D
C
D
D
36
A
D
B
A
D
D
A
A
C
D
D
B
37
A
B
C
B
C
B
A
C
A
A
A
A
38
A
D
B
C
D
B
B
C
A
C
A
B
39
D
C
B
C
B
D
D
A
A
A
B
A
40
C
C
B
C
C
D
A
A
C
D
A
A
41
A
A
D
D
A
B
A
B
C
D
C
C
42
D
D
D
C
B
C
D
D
A
B
C
B
43
C
D
A
D
C
D
B
C
D
B
B
C
44
C
C
D
C
D
C
D
B
B
B
C
D
45
A
D
A
B
B
A
B
B
C
C
D
C
46
B
A
B
D
A
A
A
D
C
D
B
B
47
D
B
D
A
D
B
D
C
A
A
B
A
48
C
B
B
D
B
A
C
C
D
C
B
C
49
B
B
A
D
A
A
C
B
C
B
C
D
50
B
D
C
C
D
A
A
D
C
A
D
D