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Problem
Problem
If in
Δ
A
B
C
\Delta ABC
Δ
A
B
C
,
c
(
a
+
b
)
cos
1
2
B
=
b
(
a
+
c
)
cos
1
2
C
c(a + b) \cos \frac{1}{2}B = b(a + c) \cos \frac{1}{2}C
c
(
a
+
b
)
cos
2
1
B
=
b
(
a
+
c
)
cos
2
1
C
, the triangle is a. isosceles b. equilateral c. right angled but not isosceles d. right angled and isosceles
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