Derivative of y*y/5

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

   1. Apply the product rule:

      $$\frac{d}{d y} f{\left(y \right)} g{\left(y \right)} = f{\left(y \right)} \frac{d}{d y} g{\left(y \right)} + g{\left(y \right)} \frac{d}{d y} f{\left(y \right)}$$

      $f{\left(y \right)} = y$; to find $\frac{d}{d y} f{\left(y \right)}$:

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

      $g{\left(y \right)} = y$; to find $\frac{d}{d y} g{\left(y \right)}$:

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

      The result is: $2 y$

   So, the result is: $\frac{2 y}{5}$

The answer is:

$$\frac{2 y}{5}$$