If `y=cos x` then `dy/dx`=?

If x=a sin t,y=b cos t, then (dy)/(dx)=

If 3sin(x y)+4cos(x y)=5 then dy/dx=

If y=sin sqrt(x)*cos sqrt(x) ,then dy/dx=

y=sin(sqrt(cos sqrt(x))) ,then dy/dx=

If y=cos^2x , then find (dy)/(dx) .

x=a(t-sin t),y=a(1+cos t) then (dy)/(dx) =

If y=cos x cos 2x cos 4x cos 8x , then (dy)/(dx)" at "x=(pi)/(2) is

If y=cos ^(-1)sin x , then dy/dx

If 3sin(x y)+4cos(x y)=5 , then (dy)/(dx)= (a) y/x (b) (3sin(x y)+4cos(x y))/(3cos(x y)-4sin(x y)) (c) (3cos(x y)+4sin(x y))/(4cos(x y)-3sin(x y)) (d) none

y=(5x)^(3cos 2x) then find (dy)/(dx) .