Prove that: `cos 10^0cos30^0cos 50^0cos 70^0=3/(16)`

Prove that: cos10^(0)cos30^(@)cos50^(@)cos70^(@)=(3)/(16)

cos10^(0)cos30^(0)cos50^(@)cos70^(0)

Prove that cos10^(@)cos30^(@)cos50^(@)cos70^(@)=(3)/(16)

Prove that: i) cos10^(@)cos30^(@)cos50^(@)cos70^(@)=3/16 ii) cos20^(@)cos40^(@)cos60^(@)cos80^(@)=1/16 iii) 4cos12^(@)cos48^(@)cos72^(@)=cos36^(@) iv) cos40^(@) cos80^(@)cos160^(@)=-1/8

Prove that cos130^@+cos110^@+cos10^@=0 .

Prove that: cos100^(@)+cos20^(0)=cos40^(@)

Prove that: cos20^(0)cos100^(@)+cos100^(@)cos140^(@)-cos140^(@)-cos140^(@)cos200^(@)=

Prove that: 4cos12^(0)cos48^(0)cos72^(0)=cos36^(@)

Prove that cos36^(@)cos72^(0)cos108^(0)cos144^(0)=(1)/(16)

Prove that: sin10^(0)sin30^(0)sin50^(@)sin70^(@)=(1)/(16)