COSA +COSB=2(1-COSC)
COSA+B/2.COSA-B/2=2SIN^2C/2
SINC/2COSA-B/2=2SIN^2C/2
COSA-B/2=2SINC/2=2COSA+B/2
COSA/2.COSB/2+SINA/2SINB/2=2(COSA/2COSB/2-SINA/2SINB/2)
3SINA/2SINB/2=COSA/2COSB/2
TANA/2TANB/2=1/3
S-b.S-c/S.S-a *
S-c.S-a/S.S-b=1/3
S-c/S=1/3
3S-3c=S
2S=3c
a+b+c=3c
a+b=2c hence sides r in AP
Moderation Team
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