See, we will we will come back to that, now you look at then an equation something like this you know, that d by d t of x plus you know some a of d by d t plus b equal to 0. What people will do you will assume a solution that x equal to x 1 into e power of something like, e power of sigma t or something. And then you will try to find out what is my x 1 of sigma, because it is or you can have actually d Square by d t square or d by d t whatever.