If A, B, C are the angles of a triangle,
then 2sin(A/2)cosec(B/2)sin(C/2) − sinAcot(B/2)
− cos A is
(1) Independent of A, B, C
(2) Function of A, B, C
(3) Function of A, B
(4) Function of B, C
If a_1 , a_2 , a_3 , a_4 are the coefficient of any
four four consecutive terms in the expansion
of (1+x)^n , then (a_1 /(a_1 +a_2 )) + (a_3 /(a_3 +a_4 )) is equal to