(cos3A+2cos5A+cos7A)/(cos A+2cos3A+cos5A)=(cos5A)/(cos3A)

Prove that: (cos4A+2cos5A+cos7A)/(cos A+2cos3A+cos5A)=(cos5A)/(cos3A)

Prove that, (cos3A+2cos5A+cos7A)/(cosA+2cos3A+cos5A)=cos2A-sin2A.tan3A

(cosA + cos3A + cos5A + cos7A)/(cosAcos2Acos4A)=

Prove that (cos 3A +2 cos 5 A + cos 7A)/( cos A + 2 cos 3 A + cos 5A) = cos 2 A - sin 2 A tan 3 A.

cos3A+cos5A+cos7A+cos15A=4cos4A cos5A cos6A

cot3A+cos5A+cos7A+cos15A=4cos4A cos5A cos6A

Prove that: (sin2A sin3A-sin4A sin5A+sin3A sin6A)/(cos2A cos3A-cos4A cos5A+cos3A cos6A)=tan A tan4A

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: (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 .

2cos x-cos3x-cos5x=