Question

and
A=
cos 90 -sin 90
BE
cos 21°+sin 21°
cos 9º+sin 90 )
cos 21°-sin 21°
C = tan 20° + tan 40° + 3 tan 20°
descending order of A, B, C is​

Answer 1

Step-by-step explanation:

sin21. cos 9-cos84.cos6

sin21.cos9-cos(90-6).cos6

sin21.cos9-sin6.cos6

1/2(2sin21.cos9-2sin6.cos6)

use formula

2sinA.cis B=sin(