Prove that: i) `tan36^(@)+tan9^(@)+tan36^(@)tan9^(@)=1`

Prove that: (a) tan 20^(@)tan40^(@)tan60^(@)tan 80^(@)=3 (b) tan9^(@)-tan27^(@)-tan63^(@)+tan81^(@)=4

Prove that: tan10^(@) tan20^(@)tan70^(@)tan80^(@)=1

Prove that tan 9^(@) - tan 27^(@) -tan 63^(@) + tan 81^(@) =4

Statement-1: sin^(2)6^(@) + sin^(2)12^(@) + sin^(2)18^(@) +……..+ sin^(2)84^(@)=7 Statement-2: tan9^(@) tan27^(@) tan45^(@) tan36^(@) tan81^(@)=1 Statement-3: (tan(pi/4) + cot(pi/4) + " cosec " pi/4) (tan(pi/4) + cot(pi/4) - " cosec "pi/4) = sec ^(2)pi/3

Prove that: tan10^(@)tan50^(@)+tan50^(@)tan70^(@)+tan70^(@)tan170^(@)=3

Prove that : tan^(-1)1+tan^(-1)2+tan^(-1)3=pi

Prove that :(tan69^@+tan 66^@)/(1-tan 69^@tan66^@)=-1

Prove that: tan^(-1)1+tan^(-1)2+tan^(-1)3=pi

If tan 25^(@)=a , prove that (tan 155^(@)-tan115^(@))/(1+tan155^(@)tan115^(@))=(1-a^(2))/(2a) .

Prove that (1+tan1^(@))(1+tan44^(@))(1+tan2^(@))(1+tan43^(@))………(1+tan22^(@))(1+tan23^(@))=2^(22) .