Question

If cosA=sinB2sinC , then ΔABC is​

Answer 1

Answer:

In ΔABC,

a

sinA

=

b

sinB

=

c

sinC

=k(say)

So,

sinA=ka

sinB=kb

sinC=kc

Where a, b, c are sides of the triangle and cosine formula is given by

cosA=

2bc

b

2

+c

2

−a

2

Now the expression is

cosA=

2sinC

sinB

putting all the value we get

2bc

b

2

+c

2

−a

2

=

2kc

kb

or b

2

+c

2

−a

2

=b

2

c=a

∴ The triangle is an isosceles.

Answer 2

Answer:

∆ABC is isosceles

Step-by-step explanation:

For explanation checkout the image provided above↑

Hope this is helpful....