Second order Definition and 602 Threads

  1. M

    Engineering How Do You Analyze a Second Order RLC Circuit for Different Responses?

    Second Order RLC CIrcuit? Homework Statement for this figure, vin(t) = -250u(-t) + 750U(t) mV, R = 0.5 ohms, L = 1 H, C = 0.01 F. Find zero-input, zero state, and complete response of both Vc(t) and IL(t) for t>0. Homework Equations ? The Attempt at a Solution I found the iL...
  2. S

    Solving 2nd Order ODE: y''+(1/x)y'=0

    Homework Statement find the general solution to the ODE: y''+(1/x)y'=0 Homework Equations The Attempt at a Solution I put this in the following form: y''=-(1/x)y' integrated both sides: y'=-ln(x)y +C I think i made a stupid mistake but i can't figure out what it is. Any help...
  3. T

    Second order partial derivatives

    Homework Statement if z= f(x) + yg(x), what can you say about zyy explain? Homework Equations The Attempt at a Solution z= f(x,yy) zyy = d/dy (dz/dy) d(partial derivative)
  4. T

    Second Order ODE - Variation of Parameters

    Homework Statement Find the general solution of the following diff. eqn. y''(t) + 4y'(t) + 4y(t) = t^(-2)*e^(-2t) where t>0 Homework Equations General soln - Φgeneral(t) + Φparticular(t) Wronskian - Φ1(t)Φ22'(t) - Φ2(t)Φ1'(t) The Attempt at a Solution I'm solving by...
  5. T

    Solve Second Order ODE: Find a Values for Zero Tendency

    Homework Statement Find all values of a for which all solutions of y''(x) + (a/x)y'(x) + (5/2)y(x) = 0 tend to zero as x tends 0+ and all values for which all solutions tend to zero as x tends to + Homework Equations The Attempt at a Solution I am not even sure where to being with this...
  6. K

    Second order ODE solution for this system?

    second order ODE solution for this system?? hello guys, I am wondering if what is the analytical solution for this system? can we solve it as a mass-spring-damper system? thanks for your helps. the rectangular part is removed from the disk. http://img3.imageshack.us/img3/3610/odev.th.jpg
  7. D

    Identifying Spectra Using First & Second Order Lines

    I know there are many ways to identify the spectra but, what are the advantages and disadvantages of using the first and second order lines to identify spectra? Please Help! If u don't want give me answer then suggest me some links. Thanks
  8. E

    Contour diagram and second order of partial derivative

    Homework Statement The following contour diagram represents the function z = f(x,y) http://img15.imageshack.us/img15/9059/contour.th.jpg (a) Is z an increasing or decreasing function of x? I'd say it's increasing as it goes towards the x-axis the contour lines value goes down (b) Is z...
  9. P

    Help solving non-linear second order DE

    could anyone help me with solving this second order differential equation? I am a noob on here so not sure how you get the mathplayer stuff on... so the equation is of the form x'' +ax' + bx^n = 0 (x^n means x to the power n, with a and b constants). i tried substituting x'=u to get a first...
  10. J

    Second Order ODE Using Laplace Transforms

    Little homework problem that I'm beating myself up over... Solve: xy'' - 2y' + xy = -2\cos x Using the method of Laplace transforms... So I do some jiggling and get to: (1+s^{2})\frac{dF}{ds}+4sF(s) = \frac{2s}{s^{2} + 1} To which I find the following solution: F(s) =...
  11. B

    Tips for Solving a 1D Second Order ODE in an Open Channel Experiment

    Hi all, My maths are very rusty and I would need some advice. I have some experimental results obtained in an open channel and got depth-averaged velocity u(y) at different cross-sectional locations y. I tried different models but there is one I don't know how to tackle. The following one...
  12. R

    Non linear second order diff eq

    I'm trying to find a substitution that works for the nonlin diffeq y''+a(y')^2-by=0 Any suggestions?
  13. J

    Help in second order ode numeric solution

    Dear all, Im trying to solve the following ode: y'' = -0.12*y + 0.4/sqrt(y^2 + 5.76) , y=y(t) , t: [-50,50] y(-50)=2.3 , y'(-50)=0 i changed it to a set of two first order ode using z=y' and solve it with finite differences. note that the right side...
  14. S

    Solving a Second Order Linear Differential Equation

    Hi, I'm having problems solving this equation; y'' -2y' +3y =0 y(0)=-1 , y'(0)=(root 2) -1 I found the auxiliary equation r^2 -2r +3 = 0 and since b^2 -4ac is less than zero this the case where r1 and r2 are complex numbers. This is as far as I get without getting stuck...
  15. Y

    How Does a Second Order High-Pass Filter Create Energy at Cutoff Frequency?

    Hey guys, I have a question about the Bode diagram of a second order high-pass filter (one with both a capacitance and an inductance). The Bode-diagram of the amplitude looks like this. http://dave.uta.edu/dillon/pspice/images/pst07g.jpg Here, the cutoff frequency is equal to about 10 kHz...
  16. V

    Second order nonlinear differential equation

    hi, i am facing problem in solving the following differential equation. help me. y''+ayy'+b=0, where y is a function of x, 'a' & 'b' are constants. i have tried substituting y'=u, which implies u'=u*dy/dx, these substitution change the equation to first order but i found no...
  17. E

    General solution of a second order nonlinear DE

    1. Homework Statement + relevant equations I have to solve http://home.vs.moe.edu.sg/linl/eqn1.gif sigma, pinfinity, rho, N are constants. To make things easier for us, we are allowed to treat T as a constant. 2. The attempt at a solution Treat T as constant...
  18. C

    Understanding Second Order PDEs: Explaining the Unit Tangent to a Curve

    Hi In my lecturer's notes he describes the unit tangent to a curve y=Y(X) as (i + Y'(X)j)/[(1+[Y'(X)]^2)^(0.5)] in an introduction to second order PDEs I'm a bit confused by this. Where did it come from? Can anyone explain Thanks
  19. S

    Matlab: Solving two second order differential equations

    Homework Statement Write a function and solver for the chaotic motion of stars in a galaxy Initial conditions: x at time zero = 0 velocity of x at time zero = 0.3 y at time zero = 0 velocity of y at time zero = 0 Time period 2 to 200 with an interval od 0.02 Homework Equations...
  20. J

    Second Order Seperable Differential Equations

    Hello and thanks to all who read this. I'm trying to teach myself applied mathematics, specifically (simple) differential equations. I've been solving them all fine, so far, but now I've come across second order DE's with a squared term, and I can't seem to get the right answer. I'll give...
  21. Z

    Linearizing a second order non-linear equation

    Homework Statement I am modeling a set of equations for a protein network. It is a feedback loop between 2 proteins. I have gotten the differential equations for this model and plan on doing an extended Kalman Filter to estimate the levels of protein in real time. However, I am having...
  22. E

    Please help Need solution to Second Order nonlinear DE

    Does anyone know how to solve the following Non-linear, second order, differential equation? A*y" + B*(y')^2 = F(t) + C where A, B, & C are constants **please note, in case the above notation isn't clear, the y' term is squared which is what makes it non-linear. Also, F(t) is time...
  23. A

    Second Order Homogeneous Differential Equation.

    I would very much appreciate if anyone can help me with this problem; I have approached it from many different angles to no avail. The position x(t) of a particle moving along the x-axis is governed by the differential equation: x'' + kx' + (n^2)x = 0 , and initially x(0) = a, x'(0) = u...
  24. V

    Power series solution to a second order o.d.e.

    Homework Statement Find the terms up to x^5 in the power series solution of the following equation y''=(1+x^{2})y Homework Equations Power series, sum from 0 to infinity y=\sum a_{n}x^{n} The Attempt at a Solution At first I just differentiated each term separately and...
  25. T

    Solving Second Order Differential Equations with Constant Coefficients

    Homework Statement I've completed this question but I don't think I've got it right. It's from a 2008 June FP1 further maths paper. There is a second part to the question I don't understand which I will post after I know I have got this part right :) Find, in terms of k, the general...
  26. K

    Why is the solution for a second order ODE -m_{l}^{2} e^{im_{l}\phi}?

    Can someone explain to me why the solution of \frac{d^{2}\Phi (\phi)}{d\phi^{2}} = -m_{l}^{2} is \Phi = e^{im_{l}\phi}?
  27. V

    Using Matlab to solve second order ODE's

    Homework Statement A projectile is fired with an initial speed of 1000 m/s at an angle α from the horizontal. A good model for the path uses an air-resistance force proportional to the square of the speed. This leads to the following equations for the acceleration in the x and y directions...
  28. R

    Second Order Differential Equation

    This is the question word for word: a) Solve the initial value problem: x'' + x = 2cos(\omega t) ; x(0) = 0 ; x'(0) = 0 ; \omega != 1 b) repeat but with \omega = 1 c) use the trigonometric identity: cos(\alpha) - cos(\beta) = -2sin(\frac{\alpha + \beta}{2})sin(\frac{\alpha - \beta}{2})...
  29. I

    Second Order Differential Equation Help

    Homework Statement A 2-\mu F capacitor is charged to 20 V and then connected across a 6-\mu H inductor forming an LC circuit. (a) Find the initial charge on the capacitor (b) At the time of connection, the initial current is zero. Assuming no resistance, find the amplitude, frequency and...
  30. R

    How to Solve a First and Second Order ODE for y(x) and u=dy/dx

    The Problem You are given: http://img530.imageshack.us/img530/4468/88346476ca9.jpg Where http://img408.imageshack.us/img408/209/53113174nt5.jpg is constant (taken as B). a) Differentiate both sides to produce a second order ODE for y(x) b) Show that it can be written as a first order ODE...
  31. A

    Solving a second order diff. equation

    Homework Statement Hi I need to solve the following: \frac{d^{2} x}{dt} + 2 b \frac{dx}{dt} + (b^2 - \frac{db}{dt}) x = 0[/tex] 2. The attempt at a solution Isn't this equivalent to??:: [itex]x^{''} + 2bx^{'}+ (b^2 - b^{'})x = 0 \iff x^2 + 2x +1 = 0 If I let b = 1. which...
  32. T

    How to Solve Second Order Differential Equations Involving Sines and Cosines?

    hello every body .I have some problem : i don't know slove the equation x"=k/m*x (1) i don't understand result of (1) is x=Asinkt+Bcoskt
  33. G

    Second Order homogeneous linear differential equation solution

    Hi everyone. I am really confused at the moment learning about Second Order homogeneous linear differential equations. I lay out the background of what I would like to understand. So I understand the actual maths that goes into the diff's, but I do not understand why it should be so, given the...
  34. F

    Calculating Equilibrium Points for a Second Order Equation

    ive been doing Xdot and Ydot questions using the formula lamda2-(a+d)lamda +ad-bc=0 where Xdot=ax+bc and ydot=cx+dy no problems so far until this question where i have the second order equation xdot dot+x-1/4x3=0 so i set Xdot dot =Ydot and therefore Xdot =y as usual but this gives me...
  35. B

    How Do You Calculate the Amplitude and Period of a Weight in Harmonic Motion?

    Homework Statement A 32 pound weight stretches 2 feet. Determine the amplitude and period of motion if the weight is released 1 foot above the equilibrium position with an initial velocity of 2 ft/s upward. How many complete vibrations will the weight have completed at the end of 4 pi seconds...
  36. R

    Second order Differential (Simple)

    Homework Statement I have no idea about how to solve the second order differential equation. Please someone help me solve this. Or provie me some articles for beginnrs. I have only basic knowldge of calculus. While solving a question at physics, I got this...
  37. B

    Bode Phase plot of a second order system

    Hey guys. I need to know how to draw a Phase Bode plot of a Second order system. I understand and can draw the Gain(Magnitude) Bode plot, but I can't seem to get the grip of the Phase one. As far as I know there is an asymptote at 0^{o} at low frequencies and an asymptote at 180^{o} at...
  38. K

    Solving a Second Order Homogeneous Differential Equation

    I just finished a final in my differential equations class. One of the problems had me solve a second order homogeneous differential equation using series. I boiled it down to this recursion relation: a_{n+2}=\frac{(n+3)a_{n}}{2(n+2)(n+1)} I found that the even coefficients work out...
  39. D

    Homogeneous second order linear ODE

    Hey; not much of a homework question, but something i was wanting to find out. Im still a first year undergraduate and just started on differential equations. We have just finished going over homogeneous 2nd order ODE's of the form: ay'' + by' + cy = 0 My texbook briefly outlines the...
  40. S

    Second Order Linear Homogeneous differential equations

    hey I am having a little trouble with this topic. Here are the questions I was set. a) Find the general solution of d^2y/dt^2 - 2(dy/dt) + y = 0. Verify your answer. b) Solve the initial value problem y'' + 4y' + 5y = 0; y(0)= -3, y'(0) = 0 c) Find a DE that has the given functions as...
  41. M

    System of Second Order, Nonhomogeneous Differential Equations

    Hello. I am an engineering student and am having trouble trying to figure out how to solve this system of second order, nonhomogeneous equations. I know how to solve a single second order, nonhomo. equation and how to solve a system of first orders, but not this one. Any help would be greatly...
  42. S

    Second order differential equations on forced vibrations

    Homework Statement A spring-mass system has a spring constant of 3 N/m. A mass of 2 kg is attached to the spring, and the motion takes place in a viscous fluid that offers a resistance numerically equal to the magnitude of the instantaneous velocity. If the system is driven by an externam...
  43. A

    First and Second Order Differential Equation

    Homework Statement a) Show that phi(t) = e^2t is a solution of y' - 2y = 0 and that C*phi(t) is also a solution for any constant C b) Show that phi(t) = 1/t is a solution of y' + y^2 = 0 for t>0 but that y = c*phi(t) is not a solution unless c = 0 or c = 1 Homework Equations What do...
  44. C

    Finding Solutions to Second Order Differential Equations with Initial Conditions

    y'' - 8y' + 16 = 0 ; y(0) = 4 ; y'(0) = 9 this should be not too bad but I am stuck in the same place. m^2 - 8m + 16 m1 = m2 = 4 y = C1e^(mx) + C2(e^(mx)) sub in y(0) = 4 4 = C1 + C2 C1 = 4-C2 y' = mC1e^(mx) + mC2e^(mx) sub in y'(0) = 9 9 = mC1 + mC2 C1 = 4 - C2...
  45. T

    Is y(t) = c1t^2 + c2 t^−1 the general solution of a second order ODE?

    Hi, I am trying to decide whether y(t) = c1t^2 + c2 t^−1, where c1 and c2 are arbitrary constants, is the general solution of the differential equation (t^2)y'' − 2y = 0 for t > 0 and justify the answer, but I don't really know how to approach it from this "side" of the problem. Any suggestions...
  46. I

    A silly question regarding general solutions to second order DE's

    It's been a while since I've had DE, and it seems I have forgotten something basic, yet crucial. In solving the Time-Independent Schrodinger Wave Equation in one dimension, I have the following: \left( -\frac{\hbar}{2m} \frac{\partial^2}{\partial x^2}+V\right) \Psi(x)=E\Psi(X)...
  47. S

    MATLAB Plotting Two First Order ODEs and Two Second Order ODEs

    Homework Statement I have two questions: 1) If i have two first order ODE y(1) and y(2) (in terms of time), i know how to plot y(1) versus time and y(2) versus time but i don't know how to plot y(2) versus y(1) 2)I have two second order ODES X''=... and Z''=... to solve this, we make the...
  48. J

    What is the solution to a nonhomogenous second order differential equation?

    [SOLVED] Nonhomogenous Second Order DE Homework Statement y'' - 2y' - 3y = -3te^{-t} SolveHomework Equations The Attempt at a Solution Well first I tried Y(t) = Ate^{-t} then Y(t) = At^2e^{-t} then Y(t) = At^3e^{-t} and Y(t) = At^3e^{-t} + Bt^2e^{-t} but I can't seem to get the correct...
  49. I

    Second order ode with non constant coeffcients

    Homework Statement y''(x)-k y^2 y'(x)=0 The Attempt at a Solution mathematica gives me this...
  50. A

    MATLAB Second order system of differential equations in Matlab

    Hi every one ! I am a final year Engineering student of IIT Madras, India. I am doing a project(finite element analysis of a structure) which requires the solution of a system of second order differential equations. equation looks like below: [M][U"]+K[U]=[F(t)] M : Mass Matrix of size...
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