I was given this question to find out the order and decide whether it is linear or non-linear.
The answer provided is third-order and linear. I can understand why it is third-order but don't get why it is linear.
My understanding of a linear equation is shown below:
1) ...+y''+y'=y occur linearly.
2) Coefficient of y, y', y'' + ... must be the variable it correspond to.
for this question, it doesn't meet the first condition where y'' is missing.
Can someone help?