# Recent content by ILens

1. ### Mathematica Mathematica Evaluation Time

Thank you! I spent some time yesterday reading posts and articles about Mathematica, and there was a guy who claimed to had waited for a notebook evaluation about 20 min. :bugeye:
2. ### Mathematica Mathematica Evaluation Time

Hello! I am interested whether it is normal for the program Mathematica to eat 99% from my CPU when evaluating a notebook. Well, it is not just some notebook, but a notebook that contains five matrices, 63 520 entries each. It would be grate, if somebody has some information on this topic.
3. ### MATLAB An Unsolvable Integral (according to Matlab)

Could you please explain what "G & R" is?
4. ### MATLAB An Unsolvable Integral (according to Matlab)

Hello! I have the following problem: I cannot solve the integral below by the means of Matlab. \int_{-\infty}^{\infty} \frac{e^{-t^2}}{\left(2-t\right)^2 + 16} dt When I write the following in Matlab >> syms t; >> y = exp(-t^2) / (16 + (2 - t)^2); >> int(y, t, -inf, inf) it...
5. ### System of differential equations - a big problem solving it

Thanks for your answer. You have just confirmed that the solution I have derived is correct :rofl: :smile: :smile:
6. ### System of differential equations - a big problem solving it

Thank you, but you told me something that I already know. I have problems deriving these equations. Would you mind being more explicit in your answer.
7. ### System of differential equations - a big problem solving it

Hi! I have a serious problem solving the following system of differential equations: m_1\ddot{x_1}=-k_1x_1-k(x_1-x_2) m_2\ddot{x_2}=-k_2x_2-k(x_2-x_1) Does anybody have an idea how to solve it? Thanks.
8. ### The Lorentz force in the MKS and CGS measurement systems

Ok Thank you! I will give it a try
9. ### The Lorentz force in the MKS and CGS measurement systems

Yes, I agree. But what about the equations of motion? If , for example, we assume that the electric field is along the y-axis and is perpendicular to the velocity, does it mean that the electric field should be only included in the equation of motion along the y-axis. If so how should the...
10. ### The Lorentz force in the MKS and CGS measurement systems

Here is the exercise that caused all the trouble: " Consider a charged particle in a constant electric and a constant magnetic field. a) Derive the equations of motion. b) Determine the solution for the velocity. c) Determine the solution for the position. d) Make a qualitative drawing...
11. ### The Lorentz force in the MKS and CGS measurement systems

Thank you for the quick reply! Thank you for the quick reply, but I still have a problem deriving the formula in CGS. Does this formula completely describe the motion of a charged particle in constant homogeneous electric and magnetic fields? Did I understand it correctly - the magnetic...
12. ### The Lorentz force in the MKS and CGS measurement systems

Hi there! I have a problem deriving the formula for the Lorenz force that I found in my lecture notes in Theoretical Mechanics. The formula is: \vec{F}=q \cdot \vec{E} + \frac{q \cdot (\vec{v} \times \vec{B})}{c} Where: \vec{F} is the Lorentz force \vec{E} is the electric...