Recent content by LinearAlgebra

so is the second part equal to (2/3)(4-x^2)^3/2 ?? you don't have to do anything with the internal part, 4-x^2 like you do with the product rule in differentiation?

sin? where did sin come into the picture? Is that the only way to do this?

How do you integrate this?? Integral of 3x^2 + (4-x^2)^(1/2) dx ?? I tried a u substitution for the 4-x^2 but what do you do with 3x^2? If someone could walk we through this, i'd greatly appreciate it...i hate being stuck on something so trivial in the middle of a problem.

Okay, I'm sorry, i still just don't get it. Can someone just explain this step by step in terms of what i should be thinking or plotting?

I know, its a stupid question. I just don't understand how to choose the points. The book has the points (1,0) (0,1) (-1,0) (0,-1) etc...how did they get this?

Ooooh. got it, thanks. so when should i use the u substitution method vs integration by parts? the u sub worked out perfectly in this case...

um. okay. well I'm not lying?? I mean i don't know how that it supposed to be constructive. do you have the name of the method, the easier way, that you would use?

We have to do line integrals and as a part of the g(x,y)dx, dy, ds..this was one of the problems i was having (actually performing the integral).

No it absolutely didnt say intgrate by parts...i'm in a higher level class and haven't touched calc in 5 years and so i forget how to do this basic operation. I looked in my old freshman yr calc book and that's what it said to do. If you have a simpler way, I'm sure that's what we should do.

But then what do you do with cost ?? how do you put that in terms of u??

Okay so here's how I did it: The general rule is Integral of udv = u*v - int(v*du) So i said that v = sin^2t dv/dt = 2sintcost du=costdt --> u=sint Integral = sin^3t - int (sin^2t*costdt)??

What is the best way to integrate this?? What is the best way to integrate -250*cost*sin^2t dt ?? I'm looking in my old calc book and it says to integrate by parts-is this the only way to do it? When I try this it makes the integral even more complicated than it was to begin with.

If you have a curve integral, what is the conceptual or physical difference between integrating G(x,y)dx, G(x,y)dy and G(x,y)ds ?? How do you know when to do either one?? Confused. :shy:

What are the general rules that one should use in graphing vector fields. I'm having a lot of trouble doing this and don't really know where to start. If you take F(x,y) = -yi + xj What should be the next step in terms of graphing? They have it drawn in our book as a bunch of vectors...

okay um nevermind i mean 0!