" 21.Solve "sin36^(@)sin72^(@)sin108^(@)sin144^(@)

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) =

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) .

Prove that: sin36^(@)s in72^(0)s in108^(0)s in144^(0)=(5)/(16)

sin36^@ sin72^@ sin108^@ sin144^@ is equal to:

sin 180^(@) sin 70^(@) + sin 16^(@) sin 36^(@)=