David Skulsky
Reputation
2,796
Next privilege 3,000 Rep.
 6h comment How to draw confidence ellipse from a covariance matrix? Did you look at this? mathematica.stackexchange.com/questions/794/… Apr14 comment Bug with DateListPlot with ToolTip with NumberForm? I get the same errors in 10.1 under Mac OS X. Apr4 comment Behavior of TimelinePlot with multiple datasets of associations So should this be tagged as a bug? Jan18 comment What to do when you encounter SystemException[“MemoryAllocationFailure” during an Optimization "What to do when you encounter SystemException[“MemoryAllocationFailure” during an Optimization"? Curse. Jan6 comment InterpolatingFunction used to work with mathematic 7 but not working with mathematica 10 What do you mean by "not working?" Dec30 comment Position from 3 dimensional acceleration data? As @DanielLichtblau pointed out, it's not clear what problem you've identified. That said, what you're trying to do is tricky, at best. Since you're doubly integrating accelerometer data, biases become a major error source (the bias is the value that the sensor indicates when it's not accelerating). Furthermore, biases drift, so correcting for them is challenging. Add to that noise and other error sources, and you've got a tough problem. Finally, you need to correct for the rotational motion of the earth... Jun4 comment Switching the ordinate and abscissa causes problem in ParametricPlot It worked because your list effectively requested two parametric plots (new[x] and x), though the second parametric plot was underspecified and thus ignored by MMA. Jun4 comment How to calculate this integral? I'm also unable to get MMA to calculate the integral symbolically. However, you can calculate it numerically for a given value of a: NIntegrate[(Exp[-a x] (x^2 - 1)^(13/2)/x^10) /. {a -> 0.1}, {x, 1, [Infinity]}] Jun3 comment How to compute this triple integral? Heh. Sometimes it's better to be lucky than to be smart! Apr25 comment How to solve a non-linear equation? I should leave this to the mathematicians, but I seriously doubt you're going to find a symbolic solution. If you want a numeric solution, you need to specify the values of a, b, c... Apr25 comment How to solve a non-linear equation? Ummm…are you looking for a symbolic solution in terms of the unknowns or a numerical solution (in which case you need to provide values for the a, b, c…). Regardless, what makes you think there is a solution? Apr25 comment Histogram scale error when using DistributionChart It seems as though there's a "minimum" bar size for HistogramDensity, which definitely distorts the distribution. Unfortunately, I can't offer a suggestion for eliminating the problem (other than to choose a different approach to plotting the distribution, such as SmoothDensity). Apr12 comment I don't understand ListCorrelate! You can learn about the function ListCorrelate in the Mathematica documentation. However, your question is ambiguous: do you want to know what ListCorrelate does? Do you want to know what Subscript does? Do you want to know how the code you posted relates to solving PDEs? Do you want to know what {1,2} represents? You need to be more precise. Mar30 comment Evaluate integral of a series @Lawerance: if you are satisfied with the answer you received from Jens (and it seems you are), then please Accept his answer. Jan24 comment Solving a linear system The first equation in Solve does not exactly match the OP's equation (40-->4), so the posted result is not correct. Jan22 comment Coloring the points in a ListPlot with the value of another function Related question: mathematica.stackexchange.com/questions/1300/… Dec16 comment First 10 digits of $\pi$ without rounding 3.141592653 :-) Dec2 comment How to improve the performance of this code I also forced innerInt to only accept numeric quantities and I set it running, but I have no idea what a "reasonable" amount of execution time is. It's going now... Nov22 comment Integrate perfomance I don't know why it's slower, but if this is a calculation you perform more than once, you may benefit by storing the results (i.e., use b[i_]:=b[i]=integral). Nov22 comment How to insert trigonometric functions into matrices' vector components? I'm still confused because A.x represents the matrix/vector multiplication of A and x, which in your example would result in {2 Sin[phi],4}, but it seems you want the first term replaced with Sin[2]. Is that correct?