Derivative of 2cos(2t)+3

1. Differentiate $2 \cos{\left(2 t \right)} + 3$ term by term:

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

      1. Let $u = 2 t$.

      2. The derivative of cosine is negative sine:

         $$\frac{d}{d u} \cos{\left(u \right)} = - \sin{\left(u \right)}$$

      3. Then, apply the chain rule. Multiply by $\frac{d}{d t} 2 t$:

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

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

            So, the result is: $2$

         The result of the chain rule is:

         $$- 2 \sin{\left(2 t \right)}$$

      So, the result is: $- 4 \sin{\left(2 t \right)}$

   2. The derivative of the constant $3$ is zero.

   The result is: $- 4 \sin{\left(2 t \right)}$

The answer is:

$$- 4 \sin{\left(2 t \right)}$$