If I understand the superposition principle of undetermined coefficients then that means we can take each part on the right hand side and solve for them using the method of undetermined coefficients. We then can add them back together and be given a particular solution for the entire differential equation. But sometimes we don't need to do that? In this problem we are to find the general form of the particular equation of this non homogeneous linear differential equation... Read more ..read more

Θ"-Θ=tsint For polynomials it is fairly straight forward what we set equal too. And for just sin and cos we match them just as easily as we do when we have a polynomial But why do we combine them when we have both a polynomial and sin or cos? why not all cosines and sines together or all powers together. Why do we need to do each combination ..read more

Curious where he got the 0 from ? is e^infinity = 0 ..read more

I am confused about something which seems to be counterintuitive. According to what I find on the internet and in books, the infinite series (5n+3)/(7n-4), as n approaches infinity, diverges. However, when I try to apply the following line of reasoning, it appears to me that this series converges. Obviously, I am thinking incorrectly, somewhere, but I just can't see where: The infinite series (5n+3)/(7n-4) can be simplified by multiplying both the numerator and the denominator... Read more ..read more

The sequence is [imath]\frac{6}{4 * 7} + \frac{6}{7 * 10} + \frac{6}{10 * 13} + ...[/imath], so I assume that it's something to do with canceling the like terms. I'm not sure how to do that with multiplication though; only addition. We're supposed to do it by finding some [imath]s_n[/imath] to represent the sum at n and then find [imath]lim_{n\rightarrow\infty}s_n[/imath ..read more

Hey guys! I have this equation and i'm kinda having trouble finding the answers. Can you help me, please? Thanks The piece below is in a wind tunnel and some flow properties were measured. • Determine the drag and lift forces on this surface. • Determine the drag and lift coefficients. Piece width = 1m Re = Ux / υ p = 1,2 kg/m³ υ = 1,46*10^-5 m²/s ..read more

The question is list 5 multiple integrals that the same with above One of the solution is here: but instead i use E = { (x,y,z) | 0<=x<=1, 0<=y<=x, y<=z<=1} U { (x,y,z) | 0<=x<=1, x<=y<=1, x<=z<=1} I thought they was the same but it not it give different result after I put f(x,y,z) =1 I can t understand why it different, it seem similiar ..read more

Hi, im having trouble with a "show" style question that forms part 1 of a multi part question, I have no problems with the rest if I take the "show" stage to be absolutly true. Some general guidance regarding the process would be appreciated. The question is as follows: A spherical pill with volume V and surface area S is swallowed and slowly dissolves in the stomach. Assume that the rate of decrease in the volume V is directly proportional to the pill's surface area. a)i) Show dV/dt =... Read more ..read more

Am I expressing the forces (n as normal reaction, f as friction force, t as in tension in rope, w as in weight) of the sandbag in the correct component format with the information given? F=Niu N=Nj T=-Ti W=-mgcos(60)j-mgsin(60)j With m being the mass of the sandbag and T being 25g. I do not know the coefficient of the static friction ..read more

How to start solving this question ..read more