Recent content by sunny110

Hi, Could anyone give me a proof for the following theorem? Theorem : Ax=0 has a non-trivial solution iff det(A)=0 Thanks in advance. /Sunny

Thanks for reply. yes, for element-wise power operation, in fact the software compute the above expression. a .^(%i+1) == exp((%i+1)*log(a)) Let us return to the main problem i.e: a=[1 2;3 4]; a^(1+i) eigenvalues and eigenvectors may be get as: -->[v,d]=spec(a) d = -...

Hi; How to raising a square matrix to the power of a complex number? for example: [1 2;3 4]^(1+i) or mathematics software such as Scilab how solve such problems? -->[1 2;3 4]^(1+%i) ans = - 0.1482039 - 0.2030943 - 0.3046414 - 0.4528453 Thanks in advance...

Thanks for your reply. I followe your advice but could you introduce me some fundamental references?

Hello; I have a basic question from FEA theory. What are the basic equations solved during .. a. Linear Static Analysis b. Nonlinear analysis b. Dynamic Analysis c. Crash analysis d. CFD e. NVH I also have a look at a wikipedia article about FEM...

A little off topic, but What numerical problems may occur? Can you name some of these problems please?

I think for Matrices, this two terms are equivalent. Is this right? But in this book we read, "It is also all too easy to turn a badly scaled problem into a genuinely ill-conditioned problem." I have reached a contradiction.

Thank you very much, HallsofIvy and JBunniii. But what is difference between a "badly scaled Matrix" and a "ill-conditioned Matrix"? Please see this page ("books.google.com/books?id=8hrDV5EbrEsC&pg=PA55" )

Hi jbunniii. Thanks for reply. I don't understand the second paragraph. Can you more explain please this paragraph or introduce some book about this subject? What's the meaning of the sentence "the matrix maps the unit sphere" ,please?

Thank you professor. You explain it very well. I have a little question: What is your meaning of "other problem"?

badly scaled Matrix?! Hello, Scilab help states that If a matrix is badly scaled or nearly singular, a warning message will be displayed: "matrix is close to singular or badly scaled." (http://help.scilab.org/docs/5.3.3/en_US/inv.html) What do these terms mean? "well scaled" ...