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#1 Help Me ! » PLEASE HElP » 2007-12-10 00:09:37
- EPhillips1989
- Replies: 1
hey im trying to revise second order differential equations but i am struggling finding the general solution for equations of the following form
taking x as a solution of the equation i am going to substitute y=x.v(x) which gives:
substituting this into the equation gives:
which simplifies to:
can anyone please show me how i can solve the general solution from this point
#2 Re: Help Me ! » eigenvalues » 2007-12-09 11:24:13
its computing the eigenvalues which im having trouble with im trying to find a factor of lambda which i can eliminate but i can not find a way
#3 Help Me ! » eigenvalues » 2007-12-08 10:04:18
- EPhillips1989
- Replies: 2
hey can anyone please help me find the eigenvalues of this matrix??
#4 Help Me ! » determinants » 2007-12-08 09:48:00
- EPhillips1989
- Replies: 9
can anyone please help me understand how to compute the determinant of the following 4x4 matrix
#5 Help Me ! » phase portraits » 2007-12-04 09:08:33
- EPhillips1989
- Replies: 0
where
A=4 B=-1 C=2 D=1
P=5
Q=6
does anyone know what kind of phase portrait it is when P>0, Q>0 and
please help!!!!
#6 Help Me ! » van der pol equation- with LaTex » 2007-12-04 08:38:24
- EPhillips1989
- Replies: 0
so far i have attempted to solve this by locating the equilibrium point
where the equilibrium points are at y=0 and x=0
i need to make a linear approximation to the equation in the vicinty of the equilibrium point and determine the behaviour of the solution.
im not sure how to linearize Y
PLEASE HELP!!!!!
#7 Help Me ! » oscillator equation » 2007-12-04 07:44:37
- EPhillips1989
- Replies: 0
(d^2x/dt^2)+sinx=1/10cost
with intial conditions x=0 and dx/dt=0 at t=0
can anyone show me how i would find the solution to the linearised version of this equation analytically??
please help!!!!:(
#8 Help Me ! » general solution » 2007-12-04 07:35:48
- EPhillips1989
- Replies: 1
can anyone help me find the general solution of the following equation:
(x)y'' +(x+1)y'-y=0
any clues as to which substitution to use would be very much appreciated thanks xxx
#9 Re: Help Me ! » paricular integral » 2007-11-27 07:55:45
if i use
y=ke^2x
i get the particular integral
-12xe^2x
does this sound correct???
#10 Help Me ! » paricular integral » 2007-11-27 07:40:48
- EPhillips1989
- Replies: 2
does anyone know what particular integral i would use to solve the differential equation
y''-5y'-6y=144xe^(2x)
please help asap!!!
#11 Help Me ! » particular integrals!!! » 2007-11-27 06:51:12
- EPhillips1989
- Replies: 1
hey i have the differential equation
y''-5y'+6y=10cosx
im supposed to solve this, so far i have done:
solve y''-5y'+y=0 to get the CF trying y=e^(kx)
y'=ke^(kx) y''=k^2e^(kx)
the auxillary equation is k^2-5k+6=0
Thus the CF is y=Ae^3x +Be^2x
Iv got to continue solving this equation does anyone know what i could set y to equal to find the PI (particular integral) please help!!!
#12 Help Me ! » matrices » 2007-11-25 22:03:53
- EPhillips1989
- Replies: 2
can anyone prove that if ad-bc=0 then the matrix A is singular(not invertible)
#13 Re: Help Me ! » invertible matrices » 2007-11-25 11:19:52
is this simply enough to write as proof???
(AB)(A)^-1= AA^-1(B)=In(B)
#14 Re: Help Me ! » invertible matrices » 2007-11-25 11:15:14
thats by definition i was trying to prove this in terms of A,B i dont see how i can apply it??:(
#15 Help Me ! » matrices » 2007-11-25 10:08:02
- EPhillips1989
- Replies: 1
suppose AB=In
can anyone prove B is invertible (non-singular)
please help!!!
#16 Help Me ! » Examples Needed » 2007-11-23 08:27:28
- EPhillips1989
- Replies: 3
can anyone please give an example of a 2x2 matrix B with B^2=0(2X2)
#17 Help Me ! » matrices » 2007-11-23 08:23:41
- EPhillips1989
- Replies: 2
let A be a nxn matrix with a row of zeros can anyone prove that A is not invertible
#18 Help Me ! » invertible matrices » 2007-11-23 07:14:11
- EPhillips1989
- Replies: 3
Let A,B be nxn matrices, such that AB=In
can anyone prove that A is invertible with inverse B
please help!!
#19 Help Me ! » matrices » 2007-11-23 07:06:22
- EPhillips1989
- Replies: 1
if a,b are nxn matrices where AB=In
does anyone know how i can prove AB is invertible if and only if A and B are both invertible??
please help will be very much appreciated xx
#20 Help Me ! » matrices » 2007-11-22 01:33:38
- EPhillips1989
- Replies: 2
hey can anyone give an example of a 3*3 matrix A and B such that AB does not equal BA
#21 Help Me ! » vectors » 2007-11-20 07:00:11
- EPhillips1989
- Replies: 1
does anyone know how to attempt to solve this question???
find the distance between the point A= (1,1,2) and the plane P:3x1+x2-5x3=2
please help xx 
#22 Help Me ! » vectors » 2007-11-20 05:17:52
- EPhillips1989
- Replies: 0
hey cananyone help me with this problem please
let P=P(A,B,C) be the planes containing A,B,C respectively. write down the parametric equation for P
when A= (0,0,0), B= (0,2,4), C= (1,1,1)
help will be much appreciated xxxx
#23 Help Me ! » integration » 2007-11-14 23:09:03
- EPhillips1989
- Replies: 2
can anyone integrate
1/tanx
please help asap!!!
#24 Re: Help Me ! » general solution for a differential equation » 2007-11-14 22:31:33
yes thats what ive done with a substitution of y=vx
#25 Help Me ! » general solution for a differential equation » 2007-11-13 09:50:50
- EPhillips1989
- Replies: 3
can anyone please help me solve the following differential equation
x(dy/dx)-y=xtan(y/x)
so far i have done
x^2(dy/dx)-yx=x^2tan(y)
looking for a solution of the LHS=0
x^2(dy/dx)-yx=0
seeking a solution of the full equation in the form y=xv(x)
dy/dx=v+x(dv/dx)
substitute in full equation
x^2(v+x(dv/dx))-xv*x=x^2tan(vx)
x^2v+x^3(dv/dx)-x^2v=x^2tan(vx)
x^3(dv/dx)=x^2tan(vx)
x(dv/dx)=tan(xv)
and then i cant go any further please help!!!!!!!