# linear

1. ### linear equation with complex variables

G'day all, How to solve the following equation please, (A, B, C,.. real constants, while X, Y are complex variables: knowing that the equations are determinate (applied for several inputs of data so that the number of variables=number of equations A+iB= Real [(C.Real(x)+D.Real(y)+...
2. ### Linear Inequality Word Problem

Two times of mother's age at present is less than three times of her age nine years ago by at least 3 years. What is the mother's age at present?
3. ### Gilbert Strang Linear Algebra

I thought it was funny that I watched his lectures before I bought his book,and in doing so, cannot read his book without hearing every single word in his voice...
4. ### Linear system

Question: Using the fact that \textbf{Ax=b} is consistent if and only if \textbf{b} is a linear combination of the columns of \textbf{A} to find a solution to \left( \begin{array}{cccc} 1 & 2 & 3 & 4 \\ 2 & 3 & 4 & 1 \\ 3 & 4 & 1 & 2 \end{array} \right)\left( \begin{array}{c} x\\ y\\...
5. ### Linear Combinations

Write the following statement in formal mathematical notation, including the sigma notation: a. Any linear combination of a finite number of linear combinations of a given set of vectors {x1,x2,...,xn}, generates a linear combination of the given set of vectors. b. Prove the statement in part a.
6. ### Fitting Linear and Quadratic Functions to Data

Hello friends! I was hoping that you might be able to help me with these two questions that I have. I know it's a lot, so if you just want to help with a portion of one of the problems that is fine. All related comments are welcome. Thanks! 1. To determine the effect of alcohol consumption, a...
7. ### non linear ode

Hi , i have a question regarding this ode system dx/dt=-y-x^3 ,dy/dt=x ,so it s a question whether this system has a periodic solution respectively an asymptotic equilibrium point and lastely describing the asymptotic behaviour for t goes to infinity of all the solutions . Thanks guys
8. ### Doubts involving integrals from linear function

Hello everyone how it's going? I just registered my account and later I'll introduce myself, okay? Please comment below in case of any English error. So let's get started... I did almost all exercises involving this subject. Can I upload the images of related exercises or I really must to...
9. ### Variation Linear Equation Problem

:mad: :furious: Problem: "The weight of an object varies inversely as the square of the distance from the center of the earth. At sea level (6400 km from the center of the earth), an astronaut weighs 100 lb. How far above the earth must the astronaut be in order to weigh 64 lb?" I generally...
10. ### help with Linear spaces:)

Hi everyone, I need linear help. Given (R ^ 3): https://ibb.co/eLAgO8 Find a finite finite set for W cutting U. Thanks. :)
11. ### Linear dependence

Why the functions cos(3x) and cos(3x+pi/2) are linearly dependent functions?
12. ### linear algebra

Hello everyone, I am kind of new in the whole linear algebra subject. My teacher gave me a question that I struggled with. I was requested to find x from a given equation: ABC^tx^-1BA^tC=AB^t Basically, he manipulated the equation in A^tB^-1A^-1 and I didn't understand the whole idea...
13. ### Modifying Solution of System of Linear Equation

Consider that we have a linear system of equations resulting in the following matrix equation $Ax=b$ where $A$ is a $3\times 3$ matrix, $x$ and $b$ are $3\times 1$ vectors. Let's assume that we know the solution of this system of equation and represent it with $y$ whose entries are given by...
14. ### Hi there! Hope I can help with this app!

Hi guys, I'm new to this forum and I hope this Android app I've developed can help you with your Algebra exercises. Link here: https://play.google.com/store/apps/details?id=com.eriochrome.matrixcalculator You just enter your matrix and get lots of info: trace, determinant, eigenvalues...
15. ### Linear Algebra App

Hi there! I've developed an app for Android which may help you guys with your linear algebra exercises. Here is the link: https://play.google.com/store/apps/details?id=com.eriochrome.matrixcalculator You enter a matrix and obtain plenty of information such as eigenvalues, eigenvectors...
16. ### Systems of Linear Equations

Hi all, need help in this. I am so confused. Suppose that in a fixed population of food consumers, there are just three brands X Y Z that share the market. Suppose that each year, 10% of brand X buyers shift to brand Y and 20% to brand Z and 20% of brand Y buyers shift to brand X and 20% to...
17. ### How to solve this word problem using conversion factors and linear function?

The situation is as follows To complete an order at a milk factory $8$ workers had processed in $9$ days working $6$ hours per day $30$ gallons of milk. To complete the job the engineer at the plant hired $2$ more workers. How many days those $10$ men working $8$ hours a day would need to...
18. ### (HELP!) Gauss-Jordan Method Word Problem

Don't even know where to start with this one - I think I have to take the given information and create a system, but I don't even understand how with the way it is worded. I'm supposed to be using the Gauss-Jordan Method. Here's all of the information. Question: You are charged with the...
19. ### Linear Independence Question #2

Am I correct that if a matrix A_{m ~X~ n} (m < n) and its rank is m. Since it has some free variables. By definition the matrix A is linear dependence. Please review the following matrix A 1.000 -1.000 1.000 5.000 -2.000 3.000 1.000 2.000 3.000 4.000 -2.000 3.000 My...
20. ### Linear application and matrix.

Hello everyone, I have a doubt. I know that the image of a generic domain vector, defined by the linear application, is equivalent to the vector-matrix product between the matrix associated with the application and a generic domain vector. Is the associated matrix that we use always built with...