What is the value of `cos^(2)31^(@)-sin^(2)59^(@)`

What is the value of (cos^(2)67^(@)-sin^(2)23^(@))?

What is the value of 4(cos^(2)(10^(@))+cos^(2)(50^(@))-sin40^(@)sin80^(@))

If cos 47^@ + sin 47^@ = k , then what is the value of cos^2 47^@ - sin^2 47^@ ?

What is the value of cos^(-1)(cos(2pi)/3)+sin^(-1)(sin(2pi)/3) ?

What is the value of 2sin15^(@) cos 15^(@)-4sin^(3)15^(@)cos15^(@) ?

What is the value of (sin 2^(@) sin 4^(@) sin 6^(@) . . . . sin^(@) 88^(@))/(cos 88^(@) cos 86^(@) cos84^(@). . . . cos2 ^(@)) (Do not use trigonometric tables )

If sin^(8)theta+cos^(8)theta-1=0 then what is the value of cos^(2)theta sin^(2)theta

Find the value of (cos^(2)20^(@)+cos^(2)70^(@))/(sin^(2)59^(@)+sin^(2)31^(@)) .

What is the value of (sin22(1^(@))/(2)+cos22(1^(@))/(2)) ?

If sin2 theta=(1)/(2) then what is the value of cos(75^(@)theta)