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 1d comment Absolute value graph sketching You still have the word "reflection" in the very first line. 1d awarded Yearling 1d comment Absolute value graph sketching Please listen to user2357112 and don't use the word "reflection" because "reflection" has a specific meaning in math which is different from what you want it to mean in this answer. Somebody at the level of the OP could become terribly confused. Mar 14 comment Is linear algebra laying the foundation for something important? @lisyarus Not just sparse but dense matrix calculations too. Imagine using finite element on a volume of space and finding out that the resulting matrix is sparse but absolutely ginormous. Then you use the boundary element method to reduce the problem by a dimension so now you have a smaller matrix but it is dense. Mar 13 comment How to tell what dimension an object is? You are probably thinking of a disc. A disc is a circle including the area inside the boundary. A circle is just the curved line which forms the boundary of the disk. The circle is 1D while the disk is 2D. Another way to think of dimension is how many degrees of freedom you have in your movement if you were stuck in a circle or a disk. If I was confined to living on a circle, then at any point on the circle, I have only one degree of freedom. I can move "left" or "right". But if I was living in a disk, I can move left/right or I can move up/down so I have two degrees of freedom. Dec 9 awarded Enlightened Dec 9 awarded Nice Answer Oct 18 comment Complexity of computing $ABx$ depends on the order of multiplication +1 Wow, never thought about it this way. Makes sense! Jun 21 awarded Nice Answer Jun 5 awarded Good Answer Jun 1 comment Real world application of Fourier series @AreaMan I was talking about the decrease in the magnitude of fourier coefficients. Basically, the smoother the function is, the faster the fourier coefficients will decrease in magnitude and hence we need fewer terms to approximate the original function well. Apr 30 awarded Yearling Jan 16 comment How to calculate the approximate zero of any polynomial function without Newton's Method? @Xoque55 Newton's method can work for $x^2+1=0$ if your starting point has a nonzero imaginary part. Jan 8 awarded Famous Question Jan 4 awarded Popular Question Dec 17 answered What are some applications of elementary linear algebra outside of math? Oct 29 accepted How to fill in these steps to evaluate this Gaussian integral? Sep 23 comment Really advanced techniques of integration (definite or indefinite) +1 Risch's algorithm has a 100 page summary. Talk about an advanced technique. Sep 4 accepted Transforming a nonlinear system to a linear system Sep 4 comment Transforming a nonlinear system to a linear system It is part of a much larger nonlinear regression problem. But this can also stand alone on its own. I have three points and I want to determine $a$, $b$, and $c$ so that the Lorentzian curve goes through those three points. If I solve the nonlinear system, I need iterative methods and a starting value. I am trying to see if I can transform it into a linear system and then use a direct linear solver without an initial value.