$In$ each $of$ Problems $1$ through $6$ determine the order $of$ the given differential equation; also state

whether the equation $is$ linear $or$ nonlinear.

$t^2\frac{d^{2}y}{d{t}^2}+t\frac{dy}{dt}+2y=sint$

$(1+y^2)\frac{d^{2}y}{d{t}^2}+t\frac{dy}{dt}+y=e^t$

$\frac{d^{4}y}{d{t}^4}+\frac{d^{3}y}{d{t}^3}+\frac{d^{2}y}{d{t}^2}+\frac{dy}{dt}+y=1$

$\frac{dy}{dt}+t{y}^2=0$

$\frac{d^{2}y}{d{t}^2}+sin(t+y)=sint$

$\frac{d^{3}y}{d{t}^3}+t\frac{dy}{dt}+(co{s}^{2}t)y=t^3$