`cos1+cos2+cos3+...+cos180`

The value of cos1^@cos2^@cos3^@....cos90^@ is

Prove that : (i) tan 5^@tan 25^@ tan 30^@tan 65^@tan 85^@=(1)/(sqrt(3)) (ii) cot 12^@cot38^@cot 52^@cot60^@cot78^@=(1)/(sqrt(3)) (iii) cos 15^@cos 35^@cosec 55^@cos 60^@cosec 75^@=(1)/(2) (iv) cos 1^@cos 2^@cos 3^@.....cos 180^@=0 (v) ((sin 49^@)/(cos 41^@))^2+ ((cos 41^@)/(sin 49^@))^2=2

Prove that: tan10^0tan15^0tan75^0tan80^0=1 tan1^0tan2^0tan3^0tan89^0=1 cos1^0cos2^0cos3^0cos180^0=0

Prove that: tan10^0tan15^0tan75^0tan80^0=1 tan1^0tan2^0tan3^0.....tan89^0=1 cos1^0cos2^0cos3^0.......cos180^0=0

cos1^@ . cos2^@ . cos3^@.........cos179^@ is equal to :

cos 1^(@)cos2^(@) cos3^(@) ..... cos 180^(@) .......

Write the value of cos1^0+cos2^0+cos3^0++cos 180^0dot

Find the value of cos 1^@ cos 2^@ cos 3^@ …….cos 89^@ …..cos 179^@ cos 180^@

If A+B+C=180^@ ,prove that cos^2A+cos^2B+cos^2C=1-2cos Acos B cos C .

The value of cos 1^@.cos 2^@.cos 3^@............cos 180^@ =………….