1. $\frac{(tan5A+tan3A)}{tan5A-tan3A}=4cos4Acos2A$

2. $cos\frac{π}{11}cos\frac{2π}{11}cos\frac{3π}{11}cos\frac{4π}{11}cos\frac{5π}{11}= \frac{1}{32}$

3. $sin⁴x + cos⁴x=1-\frac{1}{2}sin²2x$

4. Prove that $cos306° + cos234° + cos162° + cos18°=0$

5. If $sinA=msinB$ , prove that,

     $tan\frac{A-B}{2}=\frac{m-1}{m+1}tan\frac{A+B}{2}$

6. $tan43°=\frac{cos2°-sin2°}{cos2°+sin2°}$