Answer 1

`(d^4y)/(dx^4) + sin(y^(′′′)) = 0`

`=> y^(′′′) + sin(y^(′′′)) = 0`

The highest order derivative present in the differential equation is `y^(′′′)` . Therefore, its order is four.

The given differential equation is not a polynomial equation in its derivatives. Hence, its degree is not defined.