sinA+sinB+sinC=4cos1/2Acos1/2Bcos1/2C

..guys can you help me in proving this one..tnx..

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- Sep 26th 2013, 07:00 PMfireboy25half angle conversion formulas
sinA+sinB+sinC=4cos1/2Acos1/2Bcos1/2C

..guys can you help me in proving this one..tnx.. - Sep 26th 2013, 07:26 PMProve ItRe: half angle conversion formulas
Yikes this is hard to read, some brackets or spaces would be nice ><

Is it $\displaystyle \displaystyle \begin{align*} \sin{(A)} + \sin{(B)} + \sin{(C)} = 4\cos{\left( \frac{A}{2} \right)} \cos{\left( \frac{B}{2}\right)}\cos{\left( \frac{C}{2}\right)} \end{align*}$? - Sep 26th 2013, 07:40 PMtopsquarkRe: half angle conversion formulas
- Sep 26th 2013, 09:21 PMibduttRe: half angle conversion formulas
Also must write the condition for this question we should have A + B + C = 180 degree.

Then use the sum and product formula: sin P + sin Q = 2 sin ( P+Q)/2 cos ( P-Q)/2 etc. - Sep 27th 2013, 01:05 PMtopsquarkRe: half angle conversion formulas
- Sep 27th 2013, 08:32 PMibduttRe: half angle conversion formulas
- Sep 29th 2013, 02:15 PMfireboy25Re: half angle conversion formulas
yes..the sum of A, B, C is 180..