" 5."sin(pi)/(10)sin(13 pi)/(10)=-(1)/(4)

Prove that: sin((pi)/(10))sin((13 pi)/(10))=-(1)/(4)

Prove that: (sin pi)/(10)+(sin(13 pi))/(10)=-(1)/(2)

sin(pi/10)sin((13pi)/10)=

sin((pi)/(10))sin((3pi)/(10))=?

Prove that: sin(9pi)/(10) + sin(13pi)/(10)=-1/2

sinpi/10+sin(13pi)/(10)=?

sin(pi/10)sin((3pi)/10)=

Prove that: sin(pi/10) sin((13pi)/10)=-1/4

Prove that: sin((pi)/(14))sin((3 pi)/(14))sin((5 pi)/(14))sin((7 pi)/(14))sin((9 pi)/(14))sin((11 pi)/(14))sin((13 pi)/(14))=(1)/(64)

The value of sin((pi)/(10))sin((13 pi)/(10)) is