Derivative of cos(4t)-sin(4t)-x

1. Differentiate $- x + \left(- \sin{\left(4 t \right)} + \cos{\left(4 t \right)}\right)$ term by term:

   1. The derivative of the constant $- \sin{\left(4 t \right)} + \cos{\left(4 t \right)}$ is zero.

   2. The derivative of a constant times a function is the constant times the derivative of the function.

      1. Apply the power rule: $x$ goes to $1$

      So, the result is: $-1$

   The result is: $-1$

The answer is:

$$-1$$