Recent content by Gogeta007

wow. . .I can't believe I missed that. . .how does really old math comes back and haunt you huh?. . .thanks a lot

Homework Statement I have a couple of problems that I am stuck on. The following: y'' - 6y' + 9y = t y(0) = 0 y'(0) = 1 and y'' - 6y' + 13y = 0 y(0) = 0 y'(0) = -3 Homework Equations y'' = s2Y(s) - sf(0) - f'(0) y' = sY(s) - f(0) y = Y(s) The Attempt at a Solution...

Homework Statement L{tcos(t)} Homework Equations Using the laplace transform find the equation. The Attempt at a Solution I already have a really long answer. . .I was just wondering if someone can explain this: Another method (appart from using integration by parts...

thanks! and how do you know where to start your n for the sumation? and where did you get k+3 from?

Homework Statement y'' + x2y' + xy = 0 Homework Equations using power series: y'' = \Sigmacnn(n-1)xn-2 (n = 2 -> infinity) y' = \Sigmacn(n-1)xn-1 (n = 1 -> infinity) y = \Sigmacnxn (n = 0 -> infinty) The Attempt at a Solution by setting the above equation with its...

Im doing my Differential Equation's homework, and I've come across some really hard problems, when it got really complicated I tuoght i was wrong (you know book's problems tend to workout nicely) . . .anyways I got REALLY stuck on this one if anyone can guide me thank you Homework Statement...

my bad. . .it is double prime not triple. *edited* thanks for pointing that out

Thank you all. I have one more y'' + y' + y = xsinx The annihilator for xsinx is (D2+1)2 which would yield 4 answers that are imaginary (+i,-i,+i,-i) when you do the particular solution, since the answers are repeating do you put an x before the constant? so far i have that...

Homework Statement 1. y''' + y'' = 8x^2 2. y'' - 2y' - 3y = 4e^x - 9 Homework Equations Annihilator for any polinomial D^n+1 annihilator for e functions = e^ax = (D-a)^n The Attempt at a Solution 1. getting the complementary eq. values of m = 0, 0, -1 yc= c1e^-x...

Sound intensity on a "flat earth" Homework Statement Consider a flat Earth with an atmosphere that descreases in density as altitude increases such that rho = rho0e-h/H where rho nought is the density of air at zero altitude and H is a constant known as the "scale height". Assume the bulk...

are there any specific "tips" on like how to work around them? from what i saw there its good to get a dy/dx somewhere (like there by dividing everything by xdx) and then doing the substitution. . . but how do you know if its better to use u=y/x or v=x/y ?

Thank you. Another question regarding my homework, same topic (differential equations) Im doing "substitution" where you have to identify that M(x,y) and N(x,y) have the same degree by doing M(tx,ty) and N(tx,ty) and such. . . substitute by u= x/y or u=y/x anyways I don't see any...

Homework Statement Im having trouble with "initial value" problems. I can't seem to grasp the "way" around it. any help is greatly appreciated. \sqrt{}1-y^2 dx - \sqrt{}1-x^2 dy = 0 y(0) = sqr(3) / 2Homework Equations solve by separation of variables and inital value. The Attempt at a...

Homework Statement There is a nonconducting rod of negligible thickness located along the x axis; its ends have coordinates x = 0 and x = L. It has a positive, nonuniform, linear charge density (lambda) = (alpha)x; alpha is constant. An infinite distance away, th eelectric potential is zero...

I don't really know how to symbolize an op amp. so i did what i could http://img260.imageshack.us/img260/7609/circuit.jpg http://img260.imageshack.us/img260/7609/circuit.jpg As I mentioned, it works fine (when it comes to making the LED blink) but I want to know how to change that...