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

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

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

If sin A = (1)/(2) then what is the value of (cot A -cos A)?

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

What is the value of 4(sin^4 30^@ + cos^4 60^@) -3(cos^2 45^@ - sin^2 90^@) ?

Answer the following by a number or a word or a sentence : What is the value of (sin^(2)22^(@)+sin^(2)68^(@))/(cos^(2)22^(@)+cos^(2)68^(@))+sin^(2)63^(@)+cos63^(@)sin27^(@) ?

If cos x + cos^2 x = 1 , then what is the value of sin^2 x + sin^4 x ?

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

What is the value of (tan 9^(@) tan 23^(@) tan 60^(@) tan67^(@) tan 81^(@))/("cosec"^(2)72^(@)+cos^(2)15^(@)-tan^(2)18^(@)+cos^(2)75^(@))? (a) (1)/(2 sqrt(3)) (b) (sqrt(3))/(2) (c) (1)/(sqrt(3)) (d) 2 sqrt(3)

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