please help! sorry my equation editor isn't working at the mo...had to resort to laptop-mousin' it.


( Read more... )

integral of (1/(1+x^2))^2 dx.

How do i go back solving this? I know 1/1+x^2 is tan inverse.. but i dont know if that will help me here.

Any pointers? Thanks!

A particle is governed by dx/dt = t3 - x3. If a particle is located at x=2 when t=2.5, can it reach the location x=1 at any later time? [Hint: t3 - x3 = (t - x)(t2 + xt + x2This question is from the Direction Fields section of my differential equations book, so we're not supposed to know how to solve it yet, and I felt I didn't have to draw out a ( Read more... )

( Read more... )

I was playing around with the differential form of Maxwell's equations trying to go through the whole derivation instead of just taking people's word for it (because that's normal for 3:00 AM). Anyways I'm getting hung up on one point in one of the vector relations: ∇⊗(∇⊗B) = ∇(∇⋅B)-∇2B. I've managed to get the mess down to a point where the ( Read more... )

Hey everyone ( Read more... )

Hello all!
I've a quick question on implicit partial differentiation...my book doesn't explain it well.

I'm trying to find dz/dx for the equation xy+x(z^3)-2yz=0.

After differentiating, I got y+3(z^2)(dz/dx)+x(z^3)-2y(dz/dx)=0

Is this the correct way to start the problem? Or did I do it with x and z reversed in purpose? Thank you!!

Howdy y'all. I have a final coming up for the first semester of BC Calculus (so Calc I, basically) in about 10 days, and I 've already worked all the problems from the book there are to work, but I still want some more practice. I was wondering if you all knew of any websites where I can get review problems to work.

water evaporates at a rate prop. to the surface area of the water.
show that the depth of the water decreases at a constant rate, regardless of the shape of the bowl.

how do i show this?
for a circle shaped bowl top, dV/dt= -(pi)(r^2)k
but what if the bowl top is an ellipse, triangle, etc?

Integral of [(cos(ln x) ]/x (dx)

How do I go about solving this? I tried u = ln x, so du = dx / x and I get integral cos u (du) but now I'm stuck..