Question

please give answer of this one question...​

Answer 1

Answer:

Cotb is the answer

Step-by-step explanation:

since a b c are in AP

therefore 2b=a+c

now

sina-Sinc/cosc-cosa

=( 2sin(a-c)/2)(cos(a+c)/2)/(2sin(a-c)/2)(sin(a+c)/2)

=(cos(a+c)/2)/(sin(a+c)/2)

=cot(a+c)/2

=cot(2b/2)

=cotb