If `E=cos^(2)71^(@)+cos^(2)49^(@)+cos71^(@) cos 49^(@)`, then the value of 10E is equal to

cos^(2)10^(@)+cos^(2)50^(@)-cos10^(@)cos50^(@) is equal to

cos^(2)5^(@) +cos^(2)10^(@) + cos^(2) 15^(@) +…..+cos^(2) 85^(@) + cos^(2) 90^(@) is equal to

If e^(cos x) -e^(-cos x) = 4 , then the value of cos x, is

If e^(cos x) -e^(-cos x) = 4 , then the value of cos x, is

If e^(cos x)-e^(-cos x) =4 , then the value of the cosx is

The value of cos ^(2) 10^(@) - cos 10^(@) cos 50^(@) + cos ^(2) 50^(@) is equal to

The value of cos^(2)10^(@)-cos10^(@)cos 50^(@)+cos^(2)50^(@) is k/2 . The value of k is ________.

((sin 33^(@))/( sin 11^(@) sin 49^(@) sin 71^(@)))^(2) + (( cos 33^(@))/(cos 11^(@) cos 49^(@) cos 71^(@)))^(2) is equal to ______.

((sin 33^(@))/( sin 11^(@) sin 49^(@) sin 71^(@)))^(2) + (( cos 33^(@))/(cos 11^(@) cos 49^(@) cos 71^(@)))^(2) is equal to ______.

((sin 33^(@))/( sin 11^(@) sin 49^(@) sin 71^(@)))^(2) + (( cos 33^(@))/(cos 11^(@) cos 49^(@) cos 71^(@)))^(2) is equal to ______.