Question

sin 4A - sin 5A + sin 9A - sin 13A/cos A - cos 5A - cos 9A + cos 13A= cot 4A​

Answer 1

Answer:

1. 2sin40.cos tita/2cos40.costita

Answer 2

Step-by-step explanation:

Using identities - sin C-sin D = 2 cos(C+D/2)sin (C-D/2)

cos C- cos D = - 2 sin (C+D/2)SIN (C-D/2)

cos C+cos D = 2 cos (C+D/2) cos (C-D/2)