Question

If $ABCD$ is a cyclic quadrilateral then $\cos(180? +A)+ \cos(180? - B) + \cos(180? - C) - \sin(90? - D) =$

• A. -1
• B. 0
• C. 1
• D. 2

Answer 1

Answer: (B)

0

Answer 2

A + C = 180? B + D = 180?