What is System of equations: Definition and 282 Discussions
In mathematics, a set of simultaneous equations, also known as a system of equations or an equation system, is a finite set of equations for which common solutions are sought. An equation system is usually classified in the same manner as single equations, namely as a:
System of linear equations,
System of nonlinear equations,
System of bilinear equations,
System of polynomial equations,
System of differential equations, or a
System of difference equations
I am trying to solve this system of differential equations using elimination method, but I am stuck.
$$\begin{cases}
y'_1 = y_2, \\
y'_2 = -y_1 + \frac{1}{\cos x}
\end{cases}$$
Here's what I tried:
I've been suggested to differentiate the ##y_1'= y_2## again to get ##y_1''= y_2'=...
For this,
I am trying to find solutions, however, I think I am getting a strange result that I am not too sure how to intercept.
I first multiply the first equation by 2 to get ##2x_1 - 8x_3 = 4## and then I add it to the second equation below to get ##0 = 1##. I think this means that there...
How can I solve a system of equations with complex numbers
2z+w=7i
zi+w=-1
I have tried substituting z with a+bi and I have tried substituting w=7i-2z but didn't get anything useful.
Edit: also, I've tried, multiplying lower eq. with -1 so that I can cancel w but I get stuck with 2z and zi and...
Summary: Can these two equations be solved for x like a system of linear inequalities, and how?
##x- 2y \le 54##
##x + y \ge 93##
We start with
##x- 2y \le 54##
##x + y \ge 93##
Multiplying the second equation by 2, we have ##2x + 2y \ge 184##. We cannot seem to cancel the y out with the...
$\tiny{2.1.5.1.c}$ source
Change the second-order IVP into a system of equations
$\dfrac{d^2x}{dt^2}+\dfrac{dx}{dt}'+4x=\sin t \quad x(0)=4\quad x'(0)= -3$
ok I presume we can rewrite this as
$u''+u'+4u=\sin t$
Let $x_1=u$ and $x_2=u'$ then $x_1'=x_2$
substituting
$x_2'+x_2+4x=\sin t$...
Change the second-order IVP into a system of equations
$y''+y'-2y=0\quad y(0)= 2\quad y'(0)=0$
let $x_1=y$ and $x_2=y'$ then $x_1'= x_2$ and $y''=x_2'$
then by substitution
$x_2'+x_2-2x_1=0$
then the system of first order of equations
$x_1'=x_2$
$x_2'=-x_2+2x_1$
hopefully so far..
$\tiny{2.1.5.1}$
Change the second-order initial-value problem into a system of equations
$x''+6x'-2x= 0\quad x(0)=1\quad x'(0)=1$
ok my first step was to do this
$e^{rt}(r^2+6r-2)=0$
using quadratic formula we get
$r=-3+\sqrt{11},\quad r=-3-\sqrt{11}$
just seeing if I going down the right road🕶
Find all solutions of the system of equations
$s(x)+s(y)=x\\ x+y+s(z)=z\\ s(x)+s(y)+s(z)=y-4$
where $x,\,y$ and $z$ are positive integers, and $s(x),\,s(y)$ and $s(z)$ are the numbers of digits in the decimal representations of $x,\,y$ and $z$ respectively.
Hi guys, I managed to solve this problem just by "rewriting" the first equation of the system as ##t=f(x)## and then substituting that in the second ##y=f(t)## equation, ending(of course) up with the sought ##f(x,y)## function.
The problem here is I didn't really understand what I have done and...
The first thing I do is making the argumented matrix:
Then I try to rearrange to make the row echelon form. But maybe that's what confusses me the most. I have tried different ways of doing it, for example changing the order of the equations. I always end up with ##k+number## expression in...
$\tiny{311.2.2.6}$
Use the inverse to solve the system
$\begin{array}{rrrrr}
7x_1&+3x_2&=-9\\
-2x_1&+x_2&=10
\end{array}$
the thing I could not get here without a calculator is $A^{-1}$
Hey! 😊
I am looking at the following exercise but I think that I miss something.
The statement is the following:
We are given the following system of equations: \begin{align*}2a-2c+d-2e=&-2 \\ -2c-2d+2e=&\ \ \ \ \ 3 \\ d+2e=&-2\end{align*}
1) Is the system in echelon form? Justify.
2)...
It makes sense that a=2 would cause problems because then we wouldn't have a matrix of full rank and we'd be unable to determine a value for w. But the key also says that when b+4a^2-4a-7≠0. Why is that an issue? For example, if a=1, that just says implies that w=0. Through back-subsitution...
Hi PF!
I'm trying to solve three equations in Mathematica, but NSolve is taking FOREVER. Am I missing perhaps an easier way? The equations are below:
NSolve[{1/2 r (r \[Theta] + (2 h + r Cos[\[Theta]]) Sin[\[Theta]]) ==
v, Cos[\[Alpha]] == -Sin[\[Theta] - \[Beta]],
Tan[\[Theta]] == (-h...
Find all the real numbers $a,\,b$ and $c$ that satisfy the following system of equations:
$\begin{align*}a + b + c &= 1\\ \dfrac{a}{ 1 - a}+\dfrac{b}{1 - b} + \dfrac{c}{1 - c} &= 6ac + 6bc = (a + 1)(b + 1)\end{align*}$
Well, i think the important here is the system, what you think about?:
-2kx2 + kx1 = mx2''
-2kx1 + kx2 + kXocos(wt) = mx1''
After this, is just solve, i found:
x2 = (k*xo*cos(wt)*(4k/m - 2w²))/(2m*(k/m - w²)*(3k/m - w²))
The cool is that if we put w equal the two normal frequency x2 tends to...
hi
given such system of equations
##
\begin{cases}
\rho^2 = 2 \rho \\
2\theta= -\theta+2k\pi , k\in \mathbb Z \\
\end{cases}
##
in the solution of the professor the system is solved is solved as follows.
##
\begin{cases}
\rho=0 , \rho=2 \\
\theta= -\frac 2 3 k\pi , k = 0,1,2 \\...
Good night!
How do I find the values of a (real) so that the solution of this system is?
(i) just an ordered pair?
(ii) exactly two pairs.
(iii) exactly 3?
(iv) is there a place where you have more than 3 pairs as an answer?So...
I thought like this: I developed the first part. I solved the...
(I hope this is not a double posting) I want to solve this system of equations, containing logarithmic terms:
##7\ln(a/b)+A = 7\ln(d/e)+D = 7\ln(g/h)+G##
##7\ln(a/c)+B = 7\ln(d/f)+E = 7\ln(g/i)+H##
##7\ln(b/c)+C = 7\ln(e/f)+F = 7\ln(h/i)+I##
##a\phi_1+d\phi_2+g\phi_3=X##...
My attempt:
According to the implicit function theorem as long as the determinant of the jacobian given by ∂(F,G)/∂(y,z) is not equal to 0, the parametrization is possible.
∂(F,G)/∂(y,z)=4yzMeaning that all points where z and y are not equal to 0 are possible parametrizations.
My friend's...
So the normal diffusion equation looks like
\frac{\partial c}{\partial t} = k\frac{\partial}{\partial x}\left(\frac{\partial c}{\partial x}\right)
I know how to get explicit and implicit solutions to this equation using finite differences. However, I am trying to do the same for an equation of...
1)
x = 3 - 4p + q
x = 3 - 4y + z
x + 4y - z = 3
2) x + 4y - z = 3
(i) let x = a and y = b, so z = a + 4b - 3
General solution:
x = a
y = b
z = a+ 4b - 3
(ii) let x = r and z = t, so y = (3 - r + t) / 4
General solution:
x = r
y = (3 - r + t) / 4
z = t3) I don't understand this part. Is the...
Hi all,
I would like to know what is the equation upon which I can use to determine the practical resonance frequencies in a system of second order, linear differential equations.
First some definitions: What I mean by practical resonance frequencies, is the frequencies that a second order...
I have equation system:
x + y + z - a*k = 0
-b*x + y + z = 0
-c*y + z = 0
-d*x + y = 0
where: a, b, c, d = const.
Have to find: x, y, z, k
Attempt of solution:
I create Matrix A with coefficients; Matrix B - Solutions (Zeros) and Matrix X - variables.
When I try to use Cramer's rule -...
I'm working on a personal math project and I'm running into this system of differential equations.
I have seen references which state the solutions are in terms of Hermite modular elliptic functions, but I do not know what those functions are. All of the references I can find on this equation...
Homework Statement
This is Rankine-Hugoniot conditions at a hydrodynamic shock front. Where P2=0 v2=0.
The problem is attached. I need to solve a system of equations. I thought it would be relatively straight forward solving for the three unknowns but I'm struggling. I know it's possible to...
Homework Statement
If an amount of $1000 is deposited in a savings account that pays 3.2% interest per year compounded monthly, the amount in the account after nmonths is given by:
The amount in the account after 2 years (rounded to one decimal point) will be??
I was just looking at indeterminate statics problems where you have a beam, three elastic wires (left, centre, and right that are holding it up), and some extra mass. (Just like example 5 in the notes below: http://fast10.vsb.cz/lausova/indeterm_all.pdf). I understand the method that was used to...
Homework Statement
This is an example worked out in the textbook Matter and Interactions, 4th Edition (pg. 181). The authors assume that solving for two unknowns is no problem, so they don’t show the steps. I’m trying to work it out and am stuck. I’ve used Alpha to get a step by step solution...
According to my text, a linear system of equations is a problem described by two or more equations in two or more variables. Now the individual equations have infinitely many solutions, however, the system of equations is said to have either exactly one solution (one point of intersection...
Homework Statement
So these are the equations of motion for a quad-copter. I am supposed to create a MATLAB model for the z-axis. In order to do this I have to linearize the equations around these points, and arrange them in state space representation.
Homework Equations
As above
The...
I have this word problem, and was wondering how I would go about creating a system of equations.
Here is the question:
Problem: You are a small forest landowner, and decide you want to sustainably harvest some of timber on your property. There are costs related to the infrastructure needed to...
As all the z coefficients are the same, it's a good idea to eliminate the z values in the second and third equations, so apply R2 - R1 to R2 and R3 - R1 to R3...
$\displaystyle \begin{align*} z &= 12 - x + 4\,y \\ 0 &= -8 + 6\,x - y \\ 0 &= -7 - 11\,x - 9\,y \end{align*}$
Now we can multiply...
The LCM of the $\displaystyle \begin{align*} x \end{align*}$ coefficients is 30, so multiplying the first equation by 6, the second by 10 and the third by 5 gives
$\displaystyle \begin{align*} 30\,x - 12\,y + 6\,z &= 18 \\ 30\,x + 10\,y + 30\,z &= 50 \\ 30\,x + 5\,y - 20\,z &= 310...
We have the linear system of equations $Ax=b$ with \begin{equation*}A=\begin{pmatrix}0 & 1 & 1 \\ 0.5 & 1.0001 & 3 \\ 1 & 2 & 4\end{pmatrix} \ \ \ \text{ und } \ \ \ b=\begin{pmatrix}2 \\ 3 \\ 4\end{pmatrix}\end{equation*}
First, I want to calculate the solution using the Gauss algorithm with...
Homework Statement
Solve the system of equations
x1-3x2-2x3=0
-x1+2x2+x3=0
2x1+4x2+6x3=0
using either Gaussian or Gauss-Jordan elimination.
Homework Equations
None.
The Attempt at a Solution
R1+R2, I got
x1-3x2-2x3=0
-x2-x3=0
2x1+4x2+6x3=0...
Homework Statement
Given the following matrix:
I need to determine the conditions for b1, b2, and b3 to make the system consistent. In addition, I need to check if the system is consistent when:
a) b1 = 1, b2 = 1, b3 = 3
b) b1 = 1, b2 = 0., b3 = -1
c) b1 = 1, b2 = 2, b3 = 3
Homework...
I am fairly new here so I apologize for any mistakes in my post.
My question concerning solving a system of equations using Gauss-Jordan Elimination is specifically about different ways to handle a possible constant. Say for instance you have three equations:
X1+X2+X3 + 3 = 9
2X1+4X2+X3 =...
Hi,
I have a set of equations that look like this:
y1 = k1*x1 + k2*x2 - A1 = 0
y2 = k3*x1 + k4*x3 - A2 = 0
y3 = k5*x2 + k6*x4 - A3 = 0
y4 = k7*x3 - A4 = 0
y5 = k8*x4 - A5 = 0
k1 to k8 are known positive constants. A1 to A5 are known positive constants (I will use...
Hi,
In a project of mine I've encountered the following set of equations:
$$ \sum_{i=1}^N \left(\frac{1}{M}\sum_{\alpha=1}^Mg_{ij}^\alpha - u_{ij}^* \right) = 0 \qquad \forall: 1\leq j \leq N$$
$$\sum_{i<j}\left( (u_{ij}^*)^2 - \frac{2}{M^2}\sum_{\alpha < \beta}^Mg_{ij}^\alpha g_{ij}^\beta...
I have 2 ellipsoids:
Ax^2/a^2+Ay^2/b^2+Az^2/c^2=1; (*a,b,c>0 constants*)
Bx^2/a^2+By^2/b^2+Bz^2/c^2=1;
Ellipsoid A rotates around axis [wax;way;waz] (unit vector) with an infinite speed;
Ellipsoid B rotates around axis [wbx;wby;wbz] (unit vector) with an infinite speed;
[Dx;Dy;Dz] is the vector...
I am solving the following system of equations (in matrix form):
##\begin{pmatrix} 1 & -2 & -1 & 1 \\ 2 & -3 & 1 & 6 \\ 3 & -5 & 0 & 7 \\ 1 & 0 & 5 & 9 \end{pmatrix}##
I want to solve it using Mathematica, but when I use the command LinearSolve[], I only get back ##\begin{pmatrix} 9 \\ 4 \\ 0...