If A is not an integral multipe of `pi` , prove that `cosAcos2Acos4Acos8A=(sin16A)/(16sinA)`

If A is not an integral multiple of (pi) , prove that cos A cos 2A cos 4A cos 8A =(sin 16A)/(16 sin A) Hence deduce that cos. (2pi)/(15). Cos. (4pi)/(15) .cos. (8pi)/(18). Cos. (16pi)/(15)=(1)/(16)

Prove that cos A cos 2A cos 4A cos 8A= (sin 16A)/(16 sin A) .

Prove that 1-8sin^2Acos^2A=cos4A

Prove that cos^4A+sin^4A+2sin^2Acos^2A=1

Prove that : cos Acos(60-A)cos(60+A)=1/4cos3A

Prove that, cos3A+cos5A+cos7A+cos15A=4cos4Acos5Acos6A .

Prove that (sin^Acos^B-cos^2Asin^2B)=(sin^2A-sin^2B)

If A, B, C are angles of a triangle , prove that sin 2A+sin 2B-sin 2C=4cos Acos B sin C

Show that (cos8Acos5A-cos12Acos9A)/(sin8Acos5A+cos12Asin9A)=tan4A