- #1
Mr.Krypton
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I'm new to this forum, anyhow thanks for the admin making such forum, doesn't matter !
I've been trying this calculation for one day still no answer,
cos (A/2)+cos (B/2)+cos (C/2)=4cos [(B+C)/4]*cos [(C+A)/4]*cos [(A+B)/4]
A+B+C = pi
Cos C+Cos D=2cos[(C+D)/2]*cos[(C-D)/2]
with above equation tried no use !
I've been trying this calculation for one day still no answer,
Homework Statement
cos (A/2)+cos (B/2)+cos (C/2)=4cos [(B+C)/4]*cos [(C+A)/4]*cos [(A+B)/4]
A+B+C = pi
Homework Equations
The Attempt at a Solution
Cos C+Cos D=2cos[(C+D)/2]*cos[(C-D)/2]
with above equation tried no use !
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