| Subject | Date Asked | Expert |
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| Need help in differential equation | 7/22/2008 | Abe Mantell |
Q: Could you please help me in solving this equation? x"' - x' = e^t. Thanks
A: First solve the corresponding homogeneous DE: x'''-x'=0 Let x(t)=e^(rt) ==> x'=r*e^(rt), ...
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| Simultaneous differential equations | 7/21/2008 | Abe Mantell |
Q: Could you please help me with this problem: (dx/x^2)+y^2 = dy/2xy = dz/(x+y)^3 *z
A: I just want to check... (dx/x^2)+y^2 = dy/2xy = dz/(x+y)^3 *z Is (dx/x^2)+y^2 correct? Should it be ...
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| families of curves | 7/13/2008 | Abe Mantell |
Q: How can i find the general solution in differential equation 1. circle with centers on the x axis. ...
A: I am a bit confused by your question. Question #1 has nothing to do with a "differential equation" ...
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| popuation problem | 7/10/2008 | Abe Mantell |
Q: I am having difficulty interpreting the notation of an equation. For the equation 1/P(dP/dt)=at+b I ...
A: Remember to include a constant of integration...so you should have obtained: ln P = [(at^2)/2]+ bt ...
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| Introduction of differential equation | 7/8/2008 | Dr. Nyayapati Swami |
Q: I am in the first year of my Bachelor level and I am trying to teach differential equation myself ...
A: The term "ordinary differential equation" refers to an equation involving an unknown function y = ...
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| Need help in solving 2 d.e. | 7/5/2008 | Dr. Nyayapati Swami |
Q: Nyayapati Swami. I have a problem on solving these 2 d.e. Can u give me some guidelines on how to ...
A: I dont see any simpler way to solve this problem as it is not an exact differential. If you have ...
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| Need help in solving 2 d.e. | 7/3/2008 | Dr. Nyayapati Swami |
Q: Nyayapati Swami. I have a problem on solving these 2 d.e. Can u give me some guidelines on how to ...
A: The second one is easy: Divide by 2y dy: [(x + 4y^2)/2y ] + dx/dy = 0 This can be written as dx/dy + ...
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| Separation of Variables | 7/1/2008 | Dr. Nyayapati Swami |
Q: I must solve using separation of varables but am unsure how to start and solve. x dx-2xy dy - 4y ...
A: x dx = 2y(x + 2) dy [x/(x + 2)] dx = 2y dy [ 1 - 2/(x + 2) ] dx = 2y dy Integrate x - 2ln(x + 2) + C ...
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| First order autonomous differential equations | 6/17/2008 | Dr. Nyayapati Swami |
Q: could you please give me some hints to solve the following system of differentia equations: ...
A: x' = x y^a, y' = y x^b These can be combined to x'/y' = y^(a-1) / x^(b-1) and hence x^(b-1) x' = ...
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| Differential Equations | 6/6/2008 | Dr. Nyayapati Swami |
Q: I was wondering if you could help me solve (i.e. differentiate): xy'=2x+3y. Thanks.
A: Rewrite the equation as y' - (3/x)y = 2 This is linear, with integrating factor e^(-3lnx) = x^(-3). ...
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| diff equation | 6/1/2008 | Dr. Nyayapati Swami |
Q: Swami, I have the general solution of a differential equation as y=Cx^2 +x. I am trying to find the ...
A: The differential equation is obtained by elimination of C from y = Cx^2 + x and dy/dx = 2Cx + 1. ...
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| continous | 5/31/2008 | Dr. Nyayapati Swami |
Q: I am megahana and undergraduate student. I am not understanding that, 1) what is exact difference ...
A: Let me explain these without using any mathematical terms. If ne draws a curve on a paper without ...
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| career counselling | 5/24/2008 | Abe Mantell |
Q: scope, prospects, and future of having msc (masters in mathematics & statistics). where can i aplly ...
A: Check these sites: http://www.ams.org/careers/ http://www.ams.org/employment ...
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| intial value problem | 5/24/2008 | Dr. Nyayapati Swami |
Q: Solve the initial value problem. dy/dx + 4y - (e^-x) = 0 , y(0)= 4/3 Im having troubles on where ...
A: This is a first order Linear equation: dy/dx + 4y = e^(-x) Integrating factor = e^(integral of 4 ) ...
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| Second Order DE solving by power series | 3/24/2008 | Dr. Nyayapati Swami |
Q: I'm stuck on solving this second order DE by power series expansion about x=0. I've got to the ...
A: It is not that difficult to get the recurrence equation for the coefficients, but what seems to be ...
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| construct | 3/7/2008 | Dr. Nyayapati Swami |
Q: !! I have a problem that knd of problem. I tried to solve but I found wrong answer. Please help!!! ...
A: Suppose V(t) is the volume, h(t) is the height and r(t) is the radius of the surface. Since a and h ...
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| review for exam | 3/4/2008 | Dr. Nyayapati Swami |
Q: y'' + 5y' + 4y = 3 with initial conditions y(0)=alfa y'(0)=beta Thanks a lot!!!
A: Auxiliary equation: m^2 + 5m + 4 = 0 which factors into (m + 4)(m + 1) = 0, and hence the roots are ...
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| differential equation | 3/2/2008 | Dr. Nyayapati Swami |
Q: dy/dx=cos^2(y/x) + (y/x) , y(1)=pi/3 Solve the inital value problem Thanks you very much!!!
A: Let v = y/x (this is the substitution used for homogeneous equations) Then vx = y and therefore ...
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| particular integrals | 2/26/2008 | Soroban |
Q: I need to find the particular integral of the inhomogeneous differential equation, ...
A: Imogen! We have: 5y'' + 4y' + y = x² I'll use the method of Undetermined Coefficients. We'll ...
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| Help!!!! | 2/25/2008 | Soroban |
Q: Find cubic polynomial expression whose roots are -1,5 and 2
A: Charu! You're in Differential Equation and you don't know about roots of polynomials? Someone ...
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| rearranging | 2/24/2008 | Soroban |
Q: I would be very grateful if you could explain how I rearrange the equation x^3dy/dx+2x^2y=5 so I can ...
A: Imogen! We have: x³(dy/dx) + 2x²y = 5 Divide by x³: dy/dx + (2/x)y = 5/x³ Find the ...
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| Differential Equations | 1/28/2008 | Soroban |
Q: can you show me the techniques of how to solve initial value problem. i have a question that says ...
A: Umeda! We have: dy/dt = (1-y^2)/y Separate the variables: y/(1-y^2) (dy) = dt Integrate: ...
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| can you help me please | 1/15/2008 | Soroban |
Q: i have a question x^3dy/dx+2x^2y=5 i need to find the general solution and find the particular ...
A: Anthony! We have: x^3(dy/dx) + 2x^2(y) = 5 Divide by x^3: (dy/dx) + (2/x)y = 5/x^3 The ...
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| can you help me please | 1/15/2008 | Abe Mantell |
Q: i have a question x^3dy/dx+2x^2y=5 find the general solution of the differential equation find the ...
A: (x^3)y'+2(x^2)y=5, dividing by x^3: ==> y'+(2/x)y=5/x^3, which is a first-order, linear ODE, we can ...
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| Amplitude frequency response | 1/14/2008 | David Moran |
Q: Could you give me an idea on how to find the amplitude frequency response for arbitrary nonlinear ...
A: I am a mathematician, however, I am not a professor. I wanted to make this correction first. As far ...
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| ???? | 1/13/2008 | Soroban |
Q: If there are 25 students in a class and they all high 5 each other 1 time how many total high fives ...
A: Bill! If you are familiar with "Combinations", the answer is: C(25,2) Otherwise, I'll ...
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| equation with the power of 3 | 1/11/2008 | Soroban |
Q: Is there any way or techniques to solve an equation with the power of 3 or even equation with higher ...
A: hafeez! Generally, the procedure is to factor the polynomial (if possible), set each factor ...
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| differential equation | 1/10/2008 | Abe Mantell |
Q: Q: solve 1/2y+1*dy/dx=cos*x/sin*x, y(pi/4)=1/2 thanks
A: So, the DE is: (1/2)y+y'=cos(x)/sin(x) with y(pi/4)=1/2...yes? ==> y'+(1/2)y=cos(x)/sin(x), is a ...
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| problem differential equation | 1/9/2008 | Abe Mantell |
Q: the height, h of a type of tree increase proportionately to the differenciate between its height at ...
A: Let h'(t)=dh/dt, thus... h' is proportional to H-h ==> h'=k(H-h), where k=the constant of ...
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| asking question | 1/9/2008 | Soroban |
Q: what is the aim and objectives of diferential equation
A: Paul! Here's my impression of Differential Equations. I've oversimplified some concepts ... bear ...
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| rational expressions | 1/8/2008 | Abe Mantell |
Q: How is doing operations (adding, subtracting, multiplying, and dividing) with rational expressions ...
A: Indeed knowing how to do arithmetic with rational numbers helps understanding the arithmetic with ...
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| help with math | 1/5/2008 | Abe Mantell |
Q: first of all I just wanted to know if the Fibonacii Sequence is a function? I was thinking that it ...
A: Yes, the Function F(n), defined as the nth Fibonacci #, is a function...since there is only one ...
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| IVP | 12/4/2007 | David Moran |
Q: I have an IVP that i am having a hard time solving. y''-3y'+2y = 3e^-t - 10cos(3t) y(0)=1, y'(0) = ...
A: I don't have time to do a complete solution, but first get the characteristic solutions. This is ...
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| Differential Equations (tank mixing) | 11/27/2007 | Dr. Nyayapati Swami |
Q: Two interconnecting tanks each holds 100 gallons of water. A solution containing 2lb/gallon of dye ...
A: There are at least two questions asked on this topic before. Here are the links and hope these ...
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| algebra | 11/24/2007 | Soroban |
Q: Could you please advise on how to solve this equation. (3 over 2x-1)+4 = (6x over 2x-1) Just an ...
A: Jim! When given an equation with fractions, we can get rid of the denominators (legally). ...
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| differential equation problem | 10/18/2007 | Soroban |
Q: I am not able to solve this initial value problem plz can u help me on that. (y+x^2y) dy/dx = 2x ...
A: Mani! The equation is Separable. Factor: y(1 + x©÷)(dy/dx} = 2x Separate: y dy = 2x/(1 + ...
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| differential equation | 10/3/2007 | Soroban |
Q: this may seem simple, but i'm just trying to get back in the groove of math before i start my next ...
A: Kim! We have: dy/dt = -y©÷ Separate variables: y^{-2} dy = - dt Integrate: -y^{-1} = -t ...
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| word problem | 10/2/2007 | Soroban |
Q: if we follow the hour and minute hands of a clock for 24 hours how many times will they form a right ...
A: JM! I'm sure there's an algebraic approach to this problem, but I can't find it. The best I ...
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| can help solve this partial differentia equation question | 9/23/2007 | Dr. Nyayapati Swami |
Q: if x=ρcos(a) and y=ρsin(a),show that ...
A: Use the chain rule and calculate the partial derivatives of V with respect to 'rho' and 'a'. Chain ...
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| pure initial value problem | 9/19/2007 | Dr. Nyayapati Swami |
Q: ut means u subscript t, and ux means u subscript x I am being asked to solve: ut + x*t*ux = 0 ...
A: Auxiliary equations: dt/1 = dx/(xt) = du/0 Hence u = c1 (c1 is a constant) t dt = dx/x (1/2)t^2 = ln ...
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