Answer: Order 3 (the differential equation is a 3rd order differential equation)
Step-by-step explanation:
Given the equation;
t3d3y/dt3 + t dy/dt + 2y = sin t
Order of a differential equation is the nth derivative of the highest derivative in the differential equation.
For the given equation the highest derivative is d^3y/dt^3, which is the 3rd derivative of y.
Therefore, the order of the differential equation is 3.