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It is called a `SetterBar`, where you can click to choose one of the given items. http://reference.wolfram.com/language/ref/SetterBar.html
The functions `KroneckerDelta[Sin[Pi x]]` and `KroneckerDelta[SawtoothWave[x]]` behave disappointingly with respect to derivation and integration: D[KroneckerDelta[Sin[Pi x]], x] D[KroneckerDelta[SawtoothWave[x]], x] ...
Using `Reduce` I get the message that it is using `FunctionExpand`: Reduce[x == q Quotient[x, q] + Mod[x, q]] In fact `FunctionExpand` translates the expression into `Floor` objects: FunctionExpand[q Quotient[x, q]] ...
I don't know why the longer time, but this seems to be a workaround: a[[1, 1 ;; 100, 1]]; // Timing a[[1, All, 1]]; // Timing
I am not sure, but you may check out `TransformedDistribution`: http://reference.wolfram.com/language/ref/TransformedDistribution.html
Just add the assumption that `t>0`.
In your first example you have evaluated the plot without entering the definition of `tpmsI`.
It is basic WL syntax: you must type `Cos[x]` instead of `cos(x)`. Or else try natural language input.
It is correct, but the choice of parameters makes it misleading as to the behaviour of the function. I would do it like this: ParametricPlot3D[{r*Cos[t], r*Sin[t], (1 - 2 r)*Sin[t]/r^2}, {r, 0, 3}, {t, 0, 2 Pi}, PlotRange -> {3...
The documentation on `RowReduce` states that > By default, symbolic expressions are considered nonzero and it gives examples on how to catch exceptions with symbolic matrices.