Write order and degree (if defined)of each of the following differential equations:

The order of a differential equation is the order of the highest derivative involved in the equation. So the order comes out to be 4 as we have and the degree is the highest power to which a derivative is raised. But when we open the Cos x series, we get This leads to an undefined power on the highest derivative. Therefore the deg9ee of this function becomes undefined.

So the answer is 4, not defined.