In this video. We're gonna go through the answer to that question 39 from chapter 9.5. Um, so yeah, but given the Matrix A which is written here, we asked Oh! Ah, derive. Uh, yeah, There is an ancestor questions A, B, C and D. I think this is quite hard questions, so I'll try and take us through it slowly. Okay? So question apart a were asked to find that I can values I come back to us basically on dso first. Find ion values. Gotta find the determinant off the matrix A minus I So basically mind seeing are from the leading diagonal. Okay, So what's that gonna be? We can evaluate it around the top itself forever. That's two minus r times by the matrix of at the seven of the Matrix to minus one minus two minus one minus. One times the matrix. December of the Matrix. No, there should be a minus. Other close. One times the matrix. 12 months, huh? Minus two minus two. Okay. Uh, I think I'll avoid boring you with the algebra for this one. Um, you guys can work that through and show that is equal Thio. Well, you can expand it all out and show that it's minus, uh, cubed. Plus three squared minus three. Ah, close one which could be fact arise to be one minus R cubed Get. So that's equal to zero than that shows the the value of ah, which are Ah, I convey values. Eyes equal to one on It's a triple. Really? Because about three here. So it's an egg value with multiplicity three. Okay, fine. Victor, that's fine. I'm vectors. We find a minus one times. I because I value this one times by you equals zero. So what is a minus? I was going to the back there. The matrix one 11 one on one minus two, minus two minus two. It comes by u equals zero. Okay, so if we let the components off, you be X y zed, then each of these rows in the matrix equation tells us the experts Why? Course said is equal to zero. Okay, so then what could solutions look like to this equation? Well, we could have that. The first term at the Ex Capone is zero. Then that would mean that Ah, the wines that components with a sign of each other. We could have that The y component is zero. In which case it'd be minus one one. Or we could have a second potent be zero. Gonna be zero minus one, but one. Okay, but now look at this guy. This equation this factor could be written in terms off this factor on this vector. So you can see that if you, uh let's see if you do this vector minus this factor that will give you this vector. So therefore, this factor is not linearly independent to these guys. So, um, where these guys are linearly independent to each other. So therefore, any item vector must pay off the form. That's, um, constant s times by the first of the linearly independent vectors. First, some constant v times a second of our linearly independent backers. Okay, so if so, have chosen this kind of arbitrarily because we could equally right. We could have equally written this guy as a linear, some off this thing guy and this guy, in which case we would change the inspector's on DDE. That would also be correct. So we've kind of written this kind of arbitrarily the point is that we kind of have only two degrees of freedom on our choice. If I came back that way, can't write the Eiken vector as a some off Constance Well supplied by all three of these. I mean, we could, but it would kind of be, ah, were necessary because we already showed that, uh, to sufficient. Just two of the of the expression, too. Give you all of the possible high in vectors to the Matrix. A. Okay, so hopefully that's Colbert. Why? We just have two vectors here. Okay, So, uh, B, this is just following standard rules for linear started different differential equations from those two aiken vectors. We can write too linearly independent solutions on They're gonna be e to the First Aiken, How you bought the only item value times T c to the t times by the first heart of the Eigen vectors on then. Secondly, Secondly, nearly defendant solution that's gonna be eats the tee times by the second darken vector. See? Okay, let's use the form that they've given us, which is x three, because t into the tea. You three plus a to the t you for. Okay, So what's the derivative of this Well, we can take out you take The city is a common factor. Used the product rule Gonna be one plus t you three plus you for times e to the t. We know that this is gonna be equal thio because what we've assumed that it's that this form is a solution to, uh, the matrix differential equation so we could have tea. That's a you three for us. Hey, you four times by E t t. Okay, so this guy and this guy are equal to each other so we can cancel each the teas and then compare coefficients off. Tease will tell us that a U three is equal to you three itself on and you have a cross compare coefficients here. This tells us that a minus by you three is equal to zero on dde a minus. I you four secret to you three. Okay, so this tells us that you three is an icon vector. That means that it needs to be of the form. Found a pot A which is s times minus one 10 close a times minus ones. They're well you asked me about for so Okay, let's try and figure out what form we're gonna take. Okay? So to figure out what you four is gonna be a we're gonna need Thio. Find out what this matrix is. A minus. Eyes the matrix one 11111 minus two minus two minus two. What time did not buy you for? And then this is gonna be equal to you three. Which, as of yet, we're unsure as to what I infected to choose. So what's gonna help us? Well, if you four has the components X y and said Just try to see you. What's that? You for its components, X. Why? And said then the top road off this equation, it's gonna tell us the expose, what was said is equal to whatever this first component is a man. The second I was gonna tell us the extras Wipers said because he was the second component third component in the third row is gonna tell us that minus two times by extra swipe, all set is equal to Okay, So then now, in order to make this house a any solutions, all we need Well, we need this component on this components were the same because otherwise would have experts watches that is equal to two things which is just mathematically consistent. So that means that, um yeah, I need those guys to be the same. So let's say that we let them be equal to one on one. Let's see whether weaken do that. Uh, yeah, definitely. Can. So that some if s is equal to you. Uh, let's see, that's equal to one. And B is equal to minus two. Then that will work. And then how does that work? That tells us that this 3rd 1 is gonna be minus two, which shows that that's gonna be minus two 11 works because now, diesel, these equations here or class into one equation which settles wipeout set is equal to walk. Forget it. So I've chosen you three to be 11 minus two. So therefore X, with y plus said where we need to choose. Yeah, a basically any backdoor that it satisfies this so we can just easily choose a vector 100 because that satisfies the equation. X plus y equals said Okay, so just finishing that off on these x three is equal to t It's the tea. 11 minus two. I saw x three. Plus it's the tea 100 we saw explore. Okay, then pot de a minus. I squared times you for equals. I was gonna be a minus. I times a minus I you for which is a that which is you three. And then we'd know from hot See, that is equal to zero. Okay, nothing. She's answer a question with the night.