Determine order and degree (if defined) of differential equations given

y″ + 2y′ + sin y = 0

It is given that equation is y’’ + 2y’ + siny = 0

We can see that the highest order derivative present in the differential is y”.

Thus, its order is two. It is polynomial equation in y” and y’

So, the highest power raised to y” is 1.

Therefore, its degree is one.