Let `f(x) =cos (cos x)`. Then which one is not correct?

Let f(x) =cos x sin 2x , then :

Let f(x)=sqrt(cos x). Then dom (f ) =?

Let f(x) =cos ^(-1) (3x-1). Then , dom (f )=?

Let f(x)=(cos^(-1)(cos x))/(x) then which of the following is(are) correct? [Note : [x] denotes greatest integer less than or equal to x.l

Let f(x)=cos x sin2x then

Let f(x) =cos^(-1) 2x. Then dom (f )=?

Let f(x)=cos x sin2x, then

Let f:R->[-1, 1] be defined as f(x) = cos(sin x), then which of the following is(are) correct ?

Let f(x)=cos^(-1)(2x^(2)-1) then

Let f:R rarr[-1,1] be defined as f(x)=cos(sin x), then which of the following is(are) correct?