So if we want to find cost function, given that the marginal pass function is C prime of X is equal to one point two x times the natural rate of one point two, and that if we produce two units, is going to cost us nine dollars and forty cents. So we might want to write down what some of these things mean first. So the marginal cost functions, remember Marginal just needs a very small change on something. So in this case, a very small change of our cost function and what this is wanting us to find or what it means, or to be a marginal cost function in terms of calculus would be the derivatives. So very small change and the way we do it, very small changes is with the derivative, so I can selection before start. I also need to know that. So if I find my cost function, C and I plugged in to Intuit, I should get nine dollars in forty four cents. So what is it telling us is, since the marginal cost function is the derivative of the cost function, I need to integrate it and plug and see it too and salt for my integration constant. So let's go ahead and write down. See, your prime of books is equal to one point two times on that log of one point two. And like I was saying, if we want to find the cost function we want to integrate this with respect to X, so integrating each side with respect to ACS so integrating the marginal cost function are the derivative of the cost function will get the CFX And then if I want to take the anti derivative of an exponential, remember that we're told that anti derivative Oh, these eh with the power k x, the X were case and Constant is going to be a k of X for a to the k X power over Okay, times the natural log day plus, um, constants. So when he teams this fact here so first we'll use the fact that scale er's can be pulled out of an interval. So it would be natural log of one point two one point two x And then I put my journal back down and now I can use the fact that we stated earlier to be so. This will be one point two acts over. So in this case, my caves in one times the natural log of my base, which is one point two and then I add on my constant up on this case, all use D for my constant since we already have a sea floating around so you can go ahead and simple fighters down. So I have a natural log during the numerator and the denominator. So those cancel out and I'll just be left with one point two x plus de is equal to my cost function. So this is just one possible cost function out of many. And if we combine this with the fact that if I produced two units is going to cost nine dollars important for sense and that all possible cost functions just given that marginal or in this form, I can end up getting that. So I need nine point four four two equal photo right function first, a one point two on the premises there, plus the and then since that sea of two I plug to him to hear and doing that on the nine point four four and then one point two squared is one point four four rusty and then solving for Dallas truck That over I get d is so using the fact that he is equal to eight and this is the general cost function I end up with a sea of X is equal to one point two x plus leaked. And so this here will be our cost function given that to unit cell for nine dollars and forty four cents.