Question

if A+B+C+D=2π
then prove
4sin(A+B/2)
​

Answer 1

Answer:

sorry I am not find this answer

Answer 2

Step-by-step explanation:

If A+B+C+D=2π, show that cosA−cosB+cosC −cosD=4sin2A+Bsin2A+Dcos2A+C.