Find the principal value of the following (i) cos^(-1) (cos 3) (ii) cos^(-1) (cos 4) (iii) cos^(-1) (cos 15) (iv) cos^(-1) (cos 30) (v) cos^(-1) (cos 50) (vi) cos^(-1) (cos.(48pi)/(7))
The value of cos12^@+cos84^@+cos156^@+cos132^@ is
The value of cos 1^@ cos 2^@ cos 3^@... cos 179^@ is
Let f( theta) = ( cos theta - "cos" (pi)/(8))(cos theta - "cos" (3 pi)/(8))(cos theta - "cos" (5 pi)/(8) )(cos theta - "cos" (7pi)/(8)) then :
Prove that 2cosx. Cos 3x- 2cos 5x. Cos 7x- cos 4x + cos12x=0 .
