Recent content by Zipi Damn

I think I will not pass the test. Thanks.

\lim_{z \to 0} \frac{sin z}{z(z+i)} I applied L'Hopital and I got: \lim_{z \to 0} \frac{cos z}{2z+i}=\frac{1}{i} Wolphram Alpha's solution is -i. What am I doing wrong?

Okay, I think I got it. Using the equation of the mayor circunference of center (0,2) and radius R=3 from Mohr's circle, we make σ=0. Then we isolate the shear stress. (σ-2)2+(τ-0)2=32 τ=√5 Now that I have the modulus, I want to know the normal direction of the plane in which shear stress...

Given the stress tensor in a point, determine the zero normal stress plane. ...2 3 0 T= 3 2 0 ...0 0 5 ---------------------- Eigenvalues: σ1=σ2=5, σ3=-1 It must be simple, but I don't know how to determine the normal vector of that plane analytically. I know σ=0. t=Tn=σ+τ=τ If normal stress...

Yes, it seems to be a mistake. But this mistake has helped me to analize better these concepts. Anyway, thank you!

I don't know why he uses cos(σ+ψ) and sin(σ+ψ) instead of cos(σ) and sin(σ) when the matrix of the second line is separated. That would make cos(σ+ψ)=cos(σ). Is this true? I can't see that relation. Because there is no similarity between the triangles formed by the vector (x,y) and the vector...

I found it solved.

I was trying to deduce the 2D Rotation Matrix and I got frustrated. So, I found this article: Ampliación del Sólido Rígido/ (in Spanish). I don't understand the second line. How does he separate the matrix in two different parts? Thanks for your time.

When you look at a cube drawn in a 2D surface, you can see a projection of the third dimension, but no the whole third dimension. When you look at a moving hypercube in the third dimension, you are seeing a projection of the fourth dimension.

Don't worry, the only thing you'll need to know by heart will be: F = ma

Homework Statement A particle of mass M is on the top of a vertical circle without initial velocity. It starts to fall clockwise. Find the angle with respect to the origin, where the particle leaves the circle. Homework Equations v=ωXr The Attempt at a Solution I used two unitary...