" 18."sin36^(@)sin72^(@)-sin108^(@)sin144^(@)" is equal to "

sin36^(@)sin72^(@)sin108^(@)sin144^(@)=(5)/(16)

sin 36^(º)sin 72^(º) sin108^(º) sin 144^(º) =

sin 36^(º)sin 72^(º) sin108^(º) sin 144^(º) =

(2sin18^(@))/(sin48^(@)sin12^(@)) is equal to

sin18^(@)-cos72^(@) is equal of :

sin^(2)17.5^(@)+sin^(2)72.5^(@) is equal to

Prove that: "sin"(pi)/(5)"sin"(2pi)/(5)"sin"(3pi)/(5)"sin"(4pi)/(5)=(5)/(16) "sin"36^(@) "sin"72^(@) "sin"108^(@) sin 144^(@)=(5)/(16) .

cos 72^@ - sin18^@ is equal to