Recent content by Purplepixie

Hello, I would like to know, if there's a closed form solution to the following problem: Given a sum of say, 3 sines, with the form y = sin(a.2.PI.t) + sin(b.2.PI.t) + sin(c.2.PI.t) where a,b,c are constants and PI = 3.141592654 and the periods in the expression are multiplication signs, what...

Thank you Country Boy, this is what I used: https://proofwiki.org/wiki/Derivative_of_Absolute_Value_Function

Thank you Skeeter, I have managed to find the answer myself, using d(sin(t))/dt = cos(t)

I would like to know how to differentiate |sin(t)| to obtain d(|sin(t)|)/d(t). Thank you!

Hi Dhamnekar, Have a look at https://en.wikipedia.org/wiki/Freezing-point_depression and especially the saltwater freezing point on that webpage. 232g NaCl looks right, per that graph. The equation for calculating the graph is given below in the same page.

Dear Klaas, Thank you for your clear and succinct explanation. I can now see where I was wrong. So much of mathematics would be simplified if representational systems could be improved! All the best, PP

Hello, I am having difficulty in translating the univariate Newton's approximation {Xn = Xn-1 - [ f(Xn-1) / f'(Xn-1)]} into the multidimensional case. My multidimensional equation system is y = F.x where y and x are (nx1) column vectors and the coefficients matrix F is (nxn), so that (nx1) =...