Recent content by BobMarly
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Laplace (IVP): Having Trouble Understanding Solution Manual's Answer
Thank you for the comment. But the problem is what it is. Besides, I'm beginning to like Laplace. Seems like there are all kinds of possibilities. Multiply RHS by 2? Not sure I need to? The homogeneous part seems to be correct, which is the first term. I think the second term has to do with...- BobMarly
- Post #3
- Forum: Calculus and Beyond Homework Help
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Laplace (IVP): Having Trouble Understanding Solution Manual's Answer
Homework Statement Use Laplace Transform to Solve IVP y"-2y'+2y=e^(-t) y(0)=0 y'(0)=1 Homework Equations [s^2*L{y}-sy(0)-y'(0)]-[2sL{y}-y(0)]+2L{y}=0 (for Homogeneous eq)The Attempt at a Solution Homogeneous Attempt: L{y}=1/(s^2-2s+2) Not sure if correct There soluton to this point is...- BobMarly
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- Ivp Laplace
- Replies: 7
- Forum: Calculus and Beyond Homework Help
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Solving IVP for Second-Order Differential Equation: x^2*y+4*x*y'+4*y=0
How do I know it satisfies the equation?- BobMarly
- Post #3
- Forum: Calculus and Beyond Homework Help
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Solving IVP for Second-Order Differential Equation: x^2*y+4*x*y'+4*y=0
Not sure of solution for IVP Homework Statement (x^2)*y"+4*x*y'+4*y=0 y(1)=1 y'(1)=2 Homework Equations Start with r(r-1)+4r+4=0 then (r^2)+3r+4=0 get (-3+/-7i)/2 The Attempt at a Solution Leads to y=C(1)e^(-3t/2)cos(7t/2)+C(2)e^(-3t/2)sin(7t/2) More y'=... one large...- BobMarly
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- Ivp
- Replies: 4
- Forum: Calculus and Beyond Homework Help
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Graduate DE: Lower Bound for radius of convergence
Prb:(x^4+4*x^2+16)y"+4(x-1)y'+6xy=0 P=(x^4+4*x^2+16) Q=4(x-1) R=6x P=0 for - 1 - 3^(1/2)*i 1 - 3^(1/2)*i - 1 + 3^(1/2)*i 1 + 3^(1/2)*i Q=0 for 1 R=0 for 0 Do we ignore Q & R, plotting P, then find shortest distance which would equal 2?- BobMarly
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- Bound Convergence Radius Radius of convergence
- Replies: 1
- Forum: Differential Equations
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High School Could an ~12ft rocket launch some sort of probe into space
That was just a qoute I heard during an interview ten or twenty years ago. If you're looking for more info, dare I say Google It!- BobMarly
- Post #17
- Forum: Astronomy and Astrophysics
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Graduate General Solution for (x^2)*y +x*y'-y=1/(x+1)
Yes, I'll read the notes. Thank you.- BobMarly
- Post #15
- Forum: Differential Equations
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High School Could an ~12ft rocket launch some sort of probe into space
I've heard it stated that the most expensive part of a launch is the first 2 inches!- BobMarly
- Post #15
- Forum: Astronomy and Astrophysics
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Graduate General Solution for (x^2)*y +x*y'-y=1/(x+1)
Maybe this is an easier question. What is the difference between x^n and a(n)x^n. The same, but only different? Is a(n)x^n used for power series? I'm sure these are one of the many processes to solving ODE. Maybe you can also point me in another direction. I understand the concept of ODE's and...- BobMarly
- Post #13
- Forum: Differential Equations
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Graduate General Solution for (x^2)*y +x*y'-y=1/(x+1)
Yes, I understand. I thought there might be some quick answers. The book we are using doesn't seem to be the greatest for beginners. I've seen what looks to me better books from the library that are ten years old. I appreciate your help. Maybe you can suggest some books or resources. Any help...- BobMarly
- Post #11
- Forum: Differential Equations
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Graduate General Solution for (x^2)*y +x*y'-y=1/(x+1)
Are these fundamental solutons? Or do I need initial values for a fundamental solution? Does this mean there are infinite amount of solutions, if so, is there a core of solutions? Or a center or solutions that the rest radiate out from?- BobMarly
- Post #9
- Forum: Differential Equations
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Graduate General Solution for (x^2)*y +x*y'-y=1/(x+1)
I don't understand why we seem to be ignoring the (x^2) and x from the original formula? And why they are not involved in the general soluton?- BobMarly
- Post #7
- Forum: Differential Equations
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Graduate General Solution for (x^2)*y +x*y'-y=1/(x+1)
Is this correct? (for the nonhomogeneous) n(n-1)x^n+nx^n-x^n=0 (n^2-n+n-1)x^n=0 (n-1)(n+1)=0 n=+/- 1 y=Ax+Bx=>y=x(A+B)- BobMarly
- Post #5
- Forum: Differential Equations
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Graduate General Solution for (x^2)*y +x*y'-y=1/(x+1)
by substition I get: (x^2)(sum(n=2))a(n)x^(n-2)+x(sum(n=1))a(n)x^(n-1)-(sum(n=0))a(n)x^(n) Not sure what to do for n=0 for terms with (x^2) and x so I can end up with the (recurance relation)*x^n.- BobMarly
- Post #3
- Forum: Differential Equations
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Graduate Find Solution 4*(x^2)*y +y=0, y(-1)=2, y'(-1)=0
I end up with 4*x^2*(sum(n=0))(n+2)*(n+1)*a(n-2)*(x^n)+(sum(n=0))a(n)*(x^n) I'm working toward the recurance relation, correct? What about the 4*x^2 for the first summation?- BobMarly
- Post #5
- Forum: Differential Equations