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  1. Bebokkos

    Multiplication of Matrix and vector

    You don't even need indices. If you have defined your matrix (A) and vector (V), just store your result in vector B=A*V. Thus, if A is (2x2) and V is (2x1) the resulting vector B is 2x1.
  2. Bebokkos

    Solving a Nonlinear DE with MathCad?

    I've discovered that Odesolve can solve this kind of DE, however it won't converge to a solution, unless the boundary becomes dy/dx=(2x)^-0.5 at x=2. If x>2 no solution is possible.
  3. Bebokkos

    Cannot solve Sin and Cosine Waves DEs

    Thank Occupant. This is exactly what I wanted. I realized what my my mistake was. Thanks a lot. If you like, take a look at my other question about the nonlinear DE.
  4. Bebokkos

    Cannot solve Sin and Cosine Waves DEs

    I got a simple system of two diff. eqs; The functions in play are: z(t)=sin(t) and w(t)=cos(t). Tried to solve the system Given z'(t) = w(t) w'(t) = -z'(t) with IC: z'(0)=1 w'(0)=0 S=Odesolve(t,8?,100) Solution fails... Even tried Rkadapt. Any ideas; (See attached MC file)..
  5. Bebokkos

    Solving a Nonlinear DE with MathCad?

    Hi! I'm currently struggling to solve the following nonlinear 2nd order DE with MC: y'' - (1/y)(y')^2 - y(dy/dx + 1) = 0 with ic: y(0)=0.235 and bc: dy/dx=(2x)^-0.5 at x=50. I've tried odesolve and rkadapt with no success. In fact, everywhere I looked I got solutions for ODE only. Can't...
  6. Bebokkos

    Iterating a Solve Block

    Right! However, it sounds complicated seeking out roots when the equation is in matrix form. I could try this in the future. Thanks again.
  7. Bebokkos

    Iterating a Solve Block

    Thanks, IRstuff. Your solution is right. However, I am not going to use it after all. The plot should produce an ellipse (joint confidence region of the two parameters), but due to the fact that MC returns one only root from the quadratic equation, the corresponding plot shows one only branch of...
  8. Bebokkos

    Iterating a Solve Block

    Thanks for the answers, but it doesn't work. The problem is that I cannot make one of the elements of vector v a range variable, since MC won't allow this. To give you a better idea I rewrite my block in detail: Vo=1 v1=1 (initial guesses) Given (v-b)'(X'X)(v-b) = F Find(v) Now, b is a...
  9. Bebokkos

    Iterating a Solve Block

    Hi I am trying to iterate a solution from a solve block, but nothing seems to work. My block contains a simple matrix equation yielding a solution for the vector v (of two elements only), i.e., Solve (v-b)'(X'X)(v-b)=G Find(v) Now, v consists of v0 and v1 elements. I want to use...

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