Question

In ΔABC, what is the value of cos B?

Answer 1

Answer:

BC/AB

Step-by-step explanation:

Answer 2

sin a = cos b

sin a = sin( 90 - b )

a = 90 - b

a+b = 90 ,

from angle sum property, we know that

in a triangle, a+b+ c = 180

c = 90°.

Now cos 90 ° = 0.

therfore, cosc = 0