The first derivative:

`(dy)/(dx)=y’=5x^4+9x^2-2`

Now for the second derivative. We just differentiate our previous answer.

`(d^2y)/(dx^2)=y”=20x^3+18x`

Now for the 3rd and 4th derivatives.

`(d^3y)/(dx^3)=y’”=60x^2+18`

`(d^4y)/(dx^4)=y^("iv")=120x`

Now the 5th derivative is

`y^"v"=120`

The 6th, 7th, 8th and all other derivatives are 0, since the derivative of a constant is 0.