Elaborate the steps to find (d²y / dx²) second order derivative of any function y = f (x)

The second-order derivative of any function is nothing but the successive derivative of its first derivative function. 

Answer: The second derivative d²y / dx² of any function, say y = 2x² + 4 comes out to be 4.

Let's look into the following steps to solve the problem.

Explanation: 

Let us first take f(x) = 2x² +4x

(d²y/dx²) can be written as  

(d²y/dx²) = d/dx (dy/dx)

Thus, first we find out dy/dx

dy/dx = d/dx (2x² + 4x)

= 4x + 4

Now,

d²y/dx² = d/dx (dy/dx) 

= d/dx (4x +4)

= 4

Thus, the second derivative of the function 2x² + 4 comes out to be 4.