Question

18. If A, B, C, D are angles of a quadrilateral, then prove that
A+B
(i) sin (A + D) + sin (B + C) = 0
(ii) sin
2
C+D
= sin
2
A+B
C + D
(iii) tan
+ tan
= 0
(iv) cosec2 (A + B) = cosec (C + D
2.
2
(v) sin A + sin (B + C + D) = 0.​

Answer 1

Answer:

1 it is the correct answer