Consider a differential equation dy/dt +(t^2)y=0. This equation is said to be a linear DE in y.Does it mean that when dy/dx is plotted in y axis and y in x axis(any one of the solutions),would the graph be a straight line?,and the next thing (t^2) is a non linear term and t^2 can be expressed as a inverse function of y which is a non linear function in y ,which when substituted in the DE obviously makes the equation non linear,but the DE is a linear equation in y ,how is that possible?