Equation of Simple Harmonic Oscillator
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So I know that the differential equation of a simple harmonic oscillator is
$dfracd^2xdt^2=-omega^2x$
and it's solution is $y = Asin(omega t+phi)$.
Now I learned for a solution with $n$ independent constants, the differential equation will be of order $n$.
In this case, there are 3 independent constants, $A, omega, phi$, so shouldn't the differential equation be of order three? How is it two?
Edit:
Also when I start with the solution itself
$y=Asin(omega t + phi)$
$y'=Aomegacos(omega t + phi)$
$dfracomega^2y^2A^2omega^2+dfracy'^2A^2w^2 = 1$
$omega^2cdot2yy'+2y'y''=0$
$omega^2=-dfracy''y$
$0=dfracyy'''-y''y'y^2$
$yy'''=y''y'$
calculus differential-equations
add a comment |Â
up vote
2
down vote
favorite
So I know that the differential equation of a simple harmonic oscillator is
$dfracd^2xdt^2=-omega^2x$
and it's solution is $y = Asin(omega t+phi)$.
Now I learned for a solution with $n$ independent constants, the differential equation will be of order $n$.
In this case, there are 3 independent constants, $A, omega, phi$, so shouldn't the differential equation be of order three? How is it two?
Edit:
Also when I start with the solution itself
$y=Asin(omega t + phi)$
$y'=Aomegacos(omega t + phi)$
$dfracomega^2y^2A^2omega^2+dfracy'^2A^2w^2 = 1$
$omega^2cdot2yy'+2y'y''=0$
$omega^2=-dfracy''y$
$0=dfracyy'''-y''y'y^2$
$yy'''=y''y'$
calculus differential-equations
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
So I know that the differential equation of a simple harmonic oscillator is
$dfracd^2xdt^2=-omega^2x$
and it's solution is $y = Asin(omega t+phi)$.
Now I learned for a solution with $n$ independent constants, the differential equation will be of order $n$.
In this case, there are 3 independent constants, $A, omega, phi$, so shouldn't the differential equation be of order three? How is it two?
Edit:
Also when I start with the solution itself
$y=Asin(omega t + phi)$
$y'=Aomegacos(omega t + phi)$
$dfracomega^2y^2A^2omega^2+dfracy'^2A^2w^2 = 1$
$omega^2cdot2yy'+2y'y''=0$
$omega^2=-dfracy''y$
$0=dfracyy'''-y''y'y^2$
$yy'''=y''y'$
calculus differential-equations
So I know that the differential equation of a simple harmonic oscillator is
$dfracd^2xdt^2=-omega^2x$
and it's solution is $y = Asin(omega t+phi)$.
Now I learned for a solution with $n$ independent constants, the differential equation will be of order $n$.
In this case, there are 3 independent constants, $A, omega, phi$, so shouldn't the differential equation be of order three? How is it two?
Edit:
Also when I start with the solution itself
$y=Asin(omega t + phi)$
$y'=Aomegacos(omega t + phi)$
$dfracomega^2y^2A^2omega^2+dfracy'^2A^2w^2 = 1$
$omega^2cdot2yy'+2y'y''=0$
$omega^2=-dfracy''y$
$0=dfracyy'''-y''y'y^2$
$yy'''=y''y'$
calculus differential-equations
calculus differential-equations
edited 2 hours ago
asked 2 hours ago
Harshit Joshi
319112
319112
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add a comment |Â
2 Answers
2
active
oldest
votes
up vote
4
down vote
accepted
Note that $A$ and $phi$ are constants depending upon the initial conditions, which is consistent with the equation of order $2$, while $omega$ depends solely upon the system that is the given equation $ddot x=-omega x$.
1
Perhaps of interest,:hyperphysics.phy-astr.gsu.edu/hbase/shm2.html
â Peter Szilas
2 hours ago
@PeterSzilas Very nice Peter! Thanks a lot
â gimusi
2 hours ago
Gimusi.Your answer is nice!The link "links" omega and the spring constant.
â Peter Szilas
2 hours ago
But like if I try to find the differential equation of the given solution by eliminating the constants, I land up at a third order equation $yy'''-y''y'$, so why is that?
â Harshit Joshi
2 hours ago
@HarshitJoshi differentiating and manipulating $ddot x=-omega x$ we obtain $dddot x=-omega dot x implies xdddot x=-omega xdot x =ddot xdot x implies xdddot x-ddot xdot x=0$ but that doesn't prove anything. The given ODE has 2 free constants which depends upon the initial condition $x(0)$ and $dot x(0)$.
â gimusi
2 hours ago
 |Â
show 7 more comments
up vote
3
down vote
The constant $omega$ is given in the equation, you mustn't count it. What you count are the adjustable constants, that you can freely tune to achieve the initial conditions.
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
4
down vote
accepted
Note that $A$ and $phi$ are constants depending upon the initial conditions, which is consistent with the equation of order $2$, while $omega$ depends solely upon the system that is the given equation $ddot x=-omega x$.
1
Perhaps of interest,:hyperphysics.phy-astr.gsu.edu/hbase/shm2.html
â Peter Szilas
2 hours ago
@PeterSzilas Very nice Peter! Thanks a lot
â gimusi
2 hours ago
Gimusi.Your answer is nice!The link "links" omega and the spring constant.
â Peter Szilas
2 hours ago
But like if I try to find the differential equation of the given solution by eliminating the constants, I land up at a third order equation $yy'''-y''y'$, so why is that?
â Harshit Joshi
2 hours ago
@HarshitJoshi differentiating and manipulating $ddot x=-omega x$ we obtain $dddot x=-omega dot x implies xdddot x=-omega xdot x =ddot xdot x implies xdddot x-ddot xdot x=0$ but that doesn't prove anything. The given ODE has 2 free constants which depends upon the initial condition $x(0)$ and $dot x(0)$.
â gimusi
2 hours ago
 |Â
show 7 more comments
up vote
4
down vote
accepted
Note that $A$ and $phi$ are constants depending upon the initial conditions, which is consistent with the equation of order $2$, while $omega$ depends solely upon the system that is the given equation $ddot x=-omega x$.
1
Perhaps of interest,:hyperphysics.phy-astr.gsu.edu/hbase/shm2.html
â Peter Szilas
2 hours ago
@PeterSzilas Very nice Peter! Thanks a lot
â gimusi
2 hours ago
Gimusi.Your answer is nice!The link "links" omega and the spring constant.
â Peter Szilas
2 hours ago
But like if I try to find the differential equation of the given solution by eliminating the constants, I land up at a third order equation $yy'''-y''y'$, so why is that?
â Harshit Joshi
2 hours ago
@HarshitJoshi differentiating and manipulating $ddot x=-omega x$ we obtain $dddot x=-omega dot x implies xdddot x=-omega xdot x =ddot xdot x implies xdddot x-ddot xdot x=0$ but that doesn't prove anything. The given ODE has 2 free constants which depends upon the initial condition $x(0)$ and $dot x(0)$.
â gimusi
2 hours ago
 |Â
show 7 more comments
up vote
4
down vote
accepted
up vote
4
down vote
accepted
Note that $A$ and $phi$ are constants depending upon the initial conditions, which is consistent with the equation of order $2$, while $omega$ depends solely upon the system that is the given equation $ddot x=-omega x$.
Note that $A$ and $phi$ are constants depending upon the initial conditions, which is consistent with the equation of order $2$, while $omega$ depends solely upon the system that is the given equation $ddot x=-omega x$.
answered 2 hours ago
gimusi
77.6k73889
77.6k73889
1
Perhaps of interest,:hyperphysics.phy-astr.gsu.edu/hbase/shm2.html
â Peter Szilas
2 hours ago
@PeterSzilas Very nice Peter! Thanks a lot
â gimusi
2 hours ago
Gimusi.Your answer is nice!The link "links" omega and the spring constant.
â Peter Szilas
2 hours ago
But like if I try to find the differential equation of the given solution by eliminating the constants, I land up at a third order equation $yy'''-y''y'$, so why is that?
â Harshit Joshi
2 hours ago
@HarshitJoshi differentiating and manipulating $ddot x=-omega x$ we obtain $dddot x=-omega dot x implies xdddot x=-omega xdot x =ddot xdot x implies xdddot x-ddot xdot x=0$ but that doesn't prove anything. The given ODE has 2 free constants which depends upon the initial condition $x(0)$ and $dot x(0)$.
â gimusi
2 hours ago
 |Â
show 7 more comments
1
Perhaps of interest,:hyperphysics.phy-astr.gsu.edu/hbase/shm2.html
â Peter Szilas
2 hours ago
@PeterSzilas Very nice Peter! Thanks a lot
â gimusi
2 hours ago
Gimusi.Your answer is nice!The link "links" omega and the spring constant.
â Peter Szilas
2 hours ago
But like if I try to find the differential equation of the given solution by eliminating the constants, I land up at a third order equation $yy'''-y''y'$, so why is that?
â Harshit Joshi
2 hours ago
@HarshitJoshi differentiating and manipulating $ddot x=-omega x$ we obtain $dddot x=-omega dot x implies xdddot x=-omega xdot x =ddot xdot x implies xdddot x-ddot xdot x=0$ but that doesn't prove anything. The given ODE has 2 free constants which depends upon the initial condition $x(0)$ and $dot x(0)$.
â gimusi
2 hours ago
1
1
Perhaps of interest,:hyperphysics.phy-astr.gsu.edu/hbase/shm2.html
â Peter Szilas
2 hours ago
Perhaps of interest,:hyperphysics.phy-astr.gsu.edu/hbase/shm2.html
â Peter Szilas
2 hours ago
@PeterSzilas Very nice Peter! Thanks a lot
â gimusi
2 hours ago
@PeterSzilas Very nice Peter! Thanks a lot
â gimusi
2 hours ago
Gimusi.Your answer is nice!The link "links" omega and the spring constant.
â Peter Szilas
2 hours ago
Gimusi.Your answer is nice!The link "links" omega and the spring constant.
â Peter Szilas
2 hours ago
But like if I try to find the differential equation of the given solution by eliminating the constants, I land up at a third order equation $yy'''-y''y'$, so why is that?
â Harshit Joshi
2 hours ago
But like if I try to find the differential equation of the given solution by eliminating the constants, I land up at a third order equation $yy'''-y''y'$, so why is that?
â Harshit Joshi
2 hours ago
@HarshitJoshi differentiating and manipulating $ddot x=-omega x$ we obtain $dddot x=-omega dot x implies xdddot x=-omega xdot x =ddot xdot x implies xdddot x-ddot xdot x=0$ but that doesn't prove anything. The given ODE has 2 free constants which depends upon the initial condition $x(0)$ and $dot x(0)$.
â gimusi
2 hours ago
@HarshitJoshi differentiating and manipulating $ddot x=-omega x$ we obtain $dddot x=-omega dot x implies xdddot x=-omega xdot x =ddot xdot x implies xdddot x-ddot xdot x=0$ but that doesn't prove anything. The given ODE has 2 free constants which depends upon the initial condition $x(0)$ and $dot x(0)$.
â gimusi
2 hours ago
 |Â
show 7 more comments
up vote
3
down vote
The constant $omega$ is given in the equation, you mustn't count it. What you count are the adjustable constants, that you can freely tune to achieve the initial conditions.
add a comment |Â
up vote
3
down vote
The constant $omega$ is given in the equation, you mustn't count it. What you count are the adjustable constants, that you can freely tune to achieve the initial conditions.
add a comment |Â
up vote
3
down vote
up vote
3
down vote
The constant $omega$ is given in the equation, you mustn't count it. What you count are the adjustable constants, that you can freely tune to achieve the initial conditions.
The constant $omega$ is given in the equation, you mustn't count it. What you count are the adjustable constants, that you can freely tune to achieve the initial conditions.
answered 1 hour ago
Yves Daoust
118k667214
118k667214
add a comment |Â
add a comment |Â
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