# Recent content by iamtrojan3

1. ### Differential equations help!

OH MY GOD. there goes 20 points that i should of gotten. thank you for the helpe.
2. ### Differential equations help!

Homework Statement this problem was on my finals and i stared at it for 30 mins straight and still didn't figure it out and now it just bothers me that i don't know how to do the first problem on my final exam. "find the general solution to the dfq" xy'+xy= 1-y Homework Equations...
3. ### Nonhomogeneous diff equations method of undeterined coeff.

Thanks alot HallsofIvy, it seems i just subbed in wrong for y''p and the "c" ended up canceling out anyways.
4. ### Nonhomogeneous diff equations method of undeterined coeff.

thanks for responding, Lets see if i have the yp's correct yp = (At^2+Bt+c)e^-t y'p = (2At + B)e^-t -(At^2+Bt+c)e^-t y''p = 2Ae^-t - (2At + B)e^-t - (2At+B)e^-t -(At^2+Bt+c)e^-t
5. ### Nonhomogeneous diff equations method of undeterined coeff.

Homework Statement Find the general solution to the diff equation using undetermined coefficients y''-2y'-3y = 3te^-1 Homework Equations The Attempt at a Solution r^2 - 2r -3 = 0 r = -1, 3 so y = c1 e^-t + c2e^3t + yp since e^-t already exists as a solution, i have to...
6. ### Differential Equations reduction of order

Homework Statement Find y2 given t^2y'' + 3ty' + y = 0 y1(t) = 1/t Homework Equations The Attempt at a Solution i found y, y' and y'' and plugged it back in to the Differential equation, after doing some work, i'm basicly down to tv''+v' = 0 where y2 = v/t so u =...
7. ### Integrating factor confusion

oh wow i thought u could bring the 2 out front.... thanks for clearing that up
8. ### Integrating factor confusion

Homework Statement Solving this differential equation ty' + 2y = t^2 - t + 1 Homework Equations Its linear so i set it up in linear form y' + y(2/t) = t - 1 +1/t The Attempt at a Solution the integrating factor (u) = e ^ integral (ydt) = e^ integral (2dt/t)... Here's the...
9. ### Floating bed problem

Homework Statement There is a large bed floating in sea with the density of 765 kg/m^3. What fraction of the bed's volume will be under the surface of the water? The density of sea water is 1035 kg/m^3. Homework Equations Fb = Density * v * gravity The Attempt at a Solution I know...
10. ### Block on a roller coaster

I got it! i didn't know that it was still a conservation problem. thanks alot for the help
11. ### Block on a roller coaster

oh crap posted wrong part >.< The block's suppose to be "A uniform solid cylinder (m=0.450 kg, of small radius)" and answer's 6.00m/s. Sorry.
12. ### Block on a roller coaster

Homework Statement A small cube (m=0.450 kg) is at a height of 393 cm up a frictionless track which has a loop of radius, R = 58.95 cm at the bottom. The cube starts from rest and slides freely down the ramp and around the loop. Find the speed of the block when it is at the top of the loop...
13. ### Weight in water

Ahh i see what i did thank you all for the help
14. ### Weight in water

Ok, now ill sound just plain stupid. How do i find the density of water?
15. ### Weight in water

Isn't that what i did? B = Density * V * g and like you said water is fairly constant, so V = B/g which is 34N/9.8 = 3.47 which is the volume of the object, right? So now i can do D = m/v for the density of the object given m of object is 341/9.8. And i just confused myself, we're ignoring the...