If A, B, C, D are angles of a cyclic quadrilateral, then prove that `cosA+cosB+cosC+cosD=0`.

If A ,B ,C ,D are angles of a cyclic quadrilateral, then prove that cos A+cos B+cos C+cos D=0

If A ,\ B ,\ C ,\ D are angles of a cyclic quadrilateral, prove that cos A+cos B+cos C+cos D=0.

If A, B, C, D be the angles of acyclic quadrilateral, show that : cosA +cosB+cosC+cosD=0 .

If A,B,C,D are the angles of a cyclic quadrilateral, show that cosA+cosB+cosC+cosD=0

If A,B,C,D are angles of a cyclic quadrilateral, then the value of cosA+cosB+cosC+cosD is

If A,B,C and D are the angles of cyclic quadrilateral, prove that: i) cosA + cosB+cosC+cosD = 0 ii) cos(180^(@)-A)+cos(180^(@)+B)+cos(180^(@)+C)-sin(90^(@)+D) = 0

Prove that cosA+cosB+cosC=1+r/R

Prove that cosA+cosB+cosC=1+r/R

If A ,\ B ,\ C ,\ D be the angles of a cyclic quadrilateral, taken in order, prove that: cos(180^0-A)+cos(180^0+B)+cos(180^0+C)-sin(90^0+D)=0

If A,B,C,D are the angles of a quadrilateral, prove that "cos"1/2(A+B)+"cos"1/2(C+D)=0 .