Question

66. (4) Here, ( sin C+sin D=x )
( Rightarrow x=sin C+sin D )
( Rightarrow x=2 cdot sin left(frac{mathrm{C}+mathrm{D}}{2}right) cdot cos left(frac{mathrm{C}-mathrm{D}}{2}right) )
( [because ) it is the basic formula of ( sin C+sin D] )

# 66. If sinc + sinD = x, then the value of x is (2) Zsin(;)cos(C+") (3) 2cool + D) cosC;") (4) 2sin ( 7 )cool®;)

Solution