`sin A sin2A + sin3A sin6A-sin 4 Asin5A = 0`

(sin A sin2A + sin3A sin6A + sin4A sin13A) / (sin A cos2A + sin3A cos6A + sin4A cos13A) = tan9A

(sin A sin2A + sin3A sin6A) / (sin A cos2A + sin3A cos6A) = tan5A

Prove that: (cos 2A cos 3A -cos 2A cos 7A + cos A cos 10A)/("sin" 4A sin 3A - sin 2A sin 5A + sin 4A sin 7A) = cot 6A cot 5A

Prove that: (cos2A\ cos3A-cos2Acos7A+cos10 A cos A)/(sin4A\ sin3A-sin2A sin5A+sin4Asin7A )=cot6A\ cot5A

Prove that: (cos 2A cos 3A-cos 2A cos 7A + cos A cos 10A)/(sin 4A sin 3A -sin 2A sin 5A + sin 4A sin 7A)= cot 6A cot 5A .

sin A+sin3A+sin5A+sin7A=

(cos2A cos3A-cos2A cos7A+cos A cos10A)/(sin4A sin3A-sin2A sin5A+sin4A sin7A)=cot6A cot5A

(cos2A cos3A-cos2A cos7A+cos A cos10A)/(sin4A sin3A-sin2A sin5A+sin4A sin7A)=cot6A*cot5A

sin2A+2sin4A+sin6A=4cos^2Asin4A

underset(x to 0)"Lt" (sin 7x-sin 5x+sin 3x-sin x)/(sin 6x-sin 4x+sin 2x)=