Recent content by Thales Costa

Homework Statement Calculate ΔH for 2 mols of Nitrogen for the following transformation: 1 bar, 21°C → 200 bar, 21°C Given that molar Cp = 4R 2. The attempt at a solution How am I supposed to find the ΔH? From what I learned, there can only be a change in enthalpy when there's a change in...

This is what I figured. I took me a while to understand that I was integrating a vector field over a surface and that the position of the surface could be shifted to the origin without changing the result. So integrating the field over x² +4y² = 1 would be the same as integrating it over the...

So I didn't need to parametrize the surface. It was a matter of just simply calculating dS, which is the cross-product between dz/dx and dz/dy. dS = √2 dA Then integrating over the surface ∫∫√2⋅dA I would get that the surface area I was looking for is √2 times the Area of the ellipse. I was...

I'm given that: S is the surface z =√(x² + y²) and (x − 2)² + 4y² ≤ 1 I tried parametrizing it using polar coordinates setting x = 2 + rcos(θ) y = 2rsin(θ) 0≤θ≤2π, 0≤r≤1 But I'm not getting the ellipse that the original equation for the domain describes So far I've tried dividing everything...

So, like this: ?

Trying on paper. Got this table. The values of Z get too high after increasing u and v by a bit. I know the surface will be a plane, but I can't visualize it in a 3D space.

Hello, I'm trying to figure out how to plot a certain vector valued function but I'm having a hard time. The problem gives me the following vector valued function: r(u,v) = <u + v, 3 - v, 1 + 4u + 5v> I don't know how to plot this. So far I've tried making a table with some u and v values to...

Got it. Thank you so much for your help!

And why is the point (-1,0) not occupied by the particle if the circle is always defined for all real numbers? Is it because making x = (1-t^2)/(1+t^2) = -1 would give me 2 = 0, therefore not possible. And plugging x= -1 in x2+y2 = -1 would give me y = 0? Sorry if it's confusing, my english is...

I see that now. Thank you for your help! The problem also asks if there are points that are not occupied by the particle as t goes from negative infinity to positive infinity. Since the vector function (cosθ, sinθ) is defined at every t from -infinity to +infinity, is it safe to say that all...

Oh my god, that's it. I did the math but for some reason I had 4t2 instead of 2t2. I should double check my math more often. Thanks for the reply. The problem also asks about the direction the particle moves as t increases, if it's counter or clockwise, and if there are points in the...

The problem asks me to show that a particle moves over a circumference with its center at the origin. The position vector of a moving particle is: I've tried using the x2+y2=r2 formula of the circumference, squaring both components of the vector function but I couldn't figure out what to do...