if `ABCD0 ` is a quadrilatral then `cos((A+B)/2)+cos((C+D)/2)=`

I: If A,B,C,D are angles of a cyclic quadrilateral then cos A + cos B + cos C + cos D=0 II : If A,B,C,D are the angles of a quadrilateral then cos""(A+B)/(2) + cos""(C+D)/(2) =0

If ABCD is a cyclic quadrilateral then cos A + cos B + cos C + cos D is equal to

If ABCD is a cyclic quadrilateral then co (180^(@) +A) + cos (180^(@) - B) +cos(180^(@)-C) - sin (90^(@) - D)=

If ABCD is a cyclic quadrilateral, then cos A + cos B is equal to............. A) 0 B) cos C + cos D C) - (cos C+ cos D) D) cos C- cos D

If ABCD is a cyclic quadrilateral then show that i) cos A + cos B + cos C + cos D = 0 ii) sin A + sin B = sin C + sin D

If ABCD is a cyclic quadrilateral, then the value of cos A - cos B + cos C - cos D =

If ABCD is a cyclic quadrilateral, then the value of cos^(2)A-cos^(2)B-cos^(2)C+cos^(2)D is ______.

If ABCD is a cyclic quadrilateral, then the value of cosA-cosB+cosC-cosD is............... A) 0 B) 1 C) 2(cos B- cos D) D) 2 (cos A- cos C)

If ABCD is a cyclic quadrilateral,then the value of cos A-cos B+cos C-cos D is

In a quadrilateral ABCD,cos A cos B+sin C sin D=