Question
ns ( cos x+cos y=-cos alpha )
( sin x+sin y=-sin alpha )
( frac{2 cos left(frac{x+y}{2}right) cos left(frac{x-y}{2}right)}{2 sin left(frac{x+y}{2}right) cos left(frac{x-y}{2}right)}=frac{cos x}{sin alpha} )
( cot left(frac{x+y}{2}right)=cot alpha )

032) Cosa + cosy + c05a=0 Sin x+sinyt sina=0 Cot(*+y= a sin a b cosa o cot a do sin saty i
Solution
