Recent content by dwilmer

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    General solution of initial value problem -dont understand problem is asking me?

    General solution of initial value problem --dont understand problem is asking me?? Homework Statement Find a value for y-sub-0 for which the solution of the initial value problem: y' - y = 1+ 3sin t y(0) - y-sub-0 remains finite as t approaches infinity. (i called it "y-sub-0" , just...
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    How to integrate something that keeps on repeating

    Homework Statement What is integral of e^t (1+3sint)? I tried integ by parts but its not working Im familiar with the technique where you end up with two idental integrals on either side, then you add one side to the other, and divide by 2. This isn't working though. Mainly because the RHS...
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    Integrating factor problems (differential equation with initial conditions)

    wow that was stupid. yup, when i multiply RHS by t^4 it works out. thanks also, what does quetion mean when it says t must be less than zero, when they already specified that t = -1?
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    Integrating factor problems (differential equation with initial conditions)

    Homework Statement Find general solution of equation (t^3)y' + (4t^2)y = e^-t with initial conditions: y(-1) = 0 and t<0 book answer gives y = -(1+t)(e^-t)/t^4 t not = 0 Homework Equations The Attempt at a Solution (t^3)y' + (4t^2)y = e^-t get integrating...
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    Solve Diff. Eq. w/ Initial Conditions: y' + 2y = te^-2t | Homework Help

    Homework Statement Solve the differential equation: y' + 2y = te^-2t with initial conditions y(1) = 0? Please show me what I am doing wrong... (or right).. also please don't show me shortcut i need to know where I am going wrong thanks. Homework Equations The Attempt at a...
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    How can you determine y's behavior from a direction field graph?

    How can you determine y's behavior from a direction field graph?? lets say i have the equation y' = 3 + 2y and i make a direction field graph. I find equilibrium position at y = -3/2. If question asks me to determine behavior of y as t approaches infinity, isn't this impossible, without...
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    What exactly does determine the behavior mean (differential equations)

    thanks for help. Could you clarify a little further, when you say: "If you draw the direction field you might get a sense of what the set of solutions to your diff. equation looks like." because I've already drawn the direction field, but what do you mean by "set of solutions"?? As far...
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    What exactly does determine the behavior mean (differential equations)

    What exactly does "determine the behavior" mean (differential equations) Homework Statement Draw a direction field for the given differential equation. Based on the diection field, determine the behavior of y as t approaches infinity. If this behavior depends on the initial value of y at...
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    Undamped Spring question problem solved, but I can't plot the graph

    Homework Statement a mass weighig 2 pounds stretches a spring 6 inches. If the mass is pulled down an additional 3 inches and then released, and if there is no damping, detemine the position, u of the mass at any time, t. Plot u verses t. Find the frequency, period and amplitute of the...
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    Mechanical ad Electrical vibration EASY question ?

    Mechanical ad Electrical vibration EASY question please help? In Boyce and Diprima textbook it says that: mu'' + ku = 0 . Then it says the general solution of this is: u = Acos (w^2)t + B sin (w^2)t , where w^2 = k/m It provides no explanation how it arrives at this. Where does...
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    Why is ATP synthesis reversible on the F1 subunit? What is the point of this?

    Why is ATP synthesis reversible on the F1 subunit? What is the point of this? Why is ATP synthesis reversible on the F1 subunit? What is the point of this? They did some experiment a long time ago where they took F1 subunit and mixed it with ATP and water, with the Oxygen radioisotope...
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