Classify the differential equations specifying the order ty

Classify the differential equations specifying the order & type (linear/non-linear): d^2x/dt^2 + 3 dx/dt = x d^3y/dx^3 = (dy/dx)^2 + dy/dx d^2y/dx^2 + 1/x dy/dx = 0 dx/dt + x = sin t.

Solution

a) second order linear

b) third order non-linear

c) second order and is non-linear because first order derivative is not multiplied by a constant

d)  first order linear