Question

if in a triangle ABC 2cosA=sinBcosecC,then​

Answer 1

If in a triangle ABC, 2 cos...

MATHS

If in a triangle ABC,2cosA=sinBcosecC, then

A .

a=h

B .

b=c

C .

c=a

D .

2a=bc

ANSWER

As we know that

sinC

sinB

=

c

b

cosA=

2bc

b

2

+c

2

−a

2

Given 2cosA=sinBcosec C

⟹2cosA=

sinC

sinB

⟹2×

2bc

b

2

+c

2

−a

2

=

c

b

⟹b

2

+c

2

−a

2

=b

2

⟹c

2

=a

2

⟹c=a

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