Recent content by oahsen

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    MATLAB A problem about residues(is matlab wrong?)

    Yes, logically it should have only one residue which is zero. However, what I did not understand is why has MATLAB find also a residue which is 1 at the pol z=i/9 ?
  2. O

    MATLAB A problem about residues(is matlab wrong?)

    I have written this simple code fragment to the MATLAB for finding the residue(s) of the function 1/(z-i/9)^3; b=[1]; a=[1 -i/3 -1/27 i/(729) ]; [r p k]=residue(b,a) and get the following result; r = 0 0 1 p = 0.0000 + 0.1111i 0.0000 + 0.1111i...
  3. O

    Parallel RLC circuit: find resonant frequency and Input at that frequency

    yes, your answer is right but I have a question in my mind. Why this is the case? Why at resonance the imaginary part should be zero? I am taking the complex analysis course but have not seen any theorem yet which suggest that the minimum of a complex function occurs where the imaginary part is...
  4. O

    Why the path independence theorem does not work?

    sorry , I made a mistyping now I corrected it. There I used the formula integral(f(z)dz) over a contour c = integral(f(z(t))* z'(t)) dt .
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    Why the path independence theorem does not work?

    Homework Statement where C is the contour given with direction marked by increasing y, and where -2≤y≤2 , compute itgeral(z^2-2z+1)dz. With the condition x=5; Firstly I solved the auestion with the classical way ; taking z= 5 + it where -2≤t≤2; we take the i*integral((5+it)^2-2(5+it)...
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    MATLAB How to use solve function in matlab in this case

    We are trying to find the roots of a function where exp(f(z)) = c. (where c is a complex number). Also f(z) is a polynomial function. The function will have the following format: expsolve( [an an-1 …] , c ) where n is the degree of “z”. For do this I took the natural logarithm of both sides...
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    MATLAB A limit problem. (Is something wrong with matlab?)

    I checked it 1000 times. This is the copy of the command window; >> syms z h; >> limit((sinh(z+h)-sinh(z))/h,h,0) ans = limit((sinh(z+h)-sinh(z))/h,h = 0)
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    MATLAB A limit problem. (Is something wrong with matlab?)

    actually this is the problem. The teacher asks us to find the derivative with; syms x; diff(sinh(x)) and after that finding it with; syms z h; limit((sinh(z+h)-sinh(z))/h,h,0) and he wants us to comment on the difference. With my matlab(R2007a) I find the first result as cosh(z) as...
  9. O

    Limit of x/(x+1) as x Goes to Infinity: Why is It 1?

    since the function behaves like the y=1 line then there is nothing wrong about its derivative to be 0 at infinity.
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    MATLAB A limit problem. (Is something wrong with matlab?)

    With the following code segment ; limit((sin(z+h)-sin(z))/h,h,0) matlab gives the result cos(z). (which is the differential of the sin(z)). However, with the code ; limit((sinh(z+h)-sinh(z))/h,h,0) matlab gives an absurd result; limit((sinh(z+h)-sinh(z))/h,h = 0) newertheless, the...
  11. O

    Where ı can find problems about first order diff. equations

    Hi. Do you know any sources where I can find good problems about first order differential equations? Thanks...
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    A problem about vectors and surfaces

    Homework Statement Find the set of all points on the surface (y + z)^2 + (z − x)^2 = 16 where the normal line is parallel to the yz-plane. Describe this set. The Attempt at a Solution I find the gradient vector of the surface then I said that the f at f*i should be zero when it is...
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    A source for calculus midterm preparation

    I am going to have an calculus exam on saturday. The topic is partial derivatives and double integrals. Does anybody know a website where I could find nice problems about these topics? Thanks already...
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    Could somebody explain this problem and solution(about partial derivatives)

    Homework Statement there is a question and a solution in this page; http://www.fen.bilkent.edu.tr/~otekman/math102/s03/m2q5.html" Please firstly examine the question and solution. (5b)... There it says f(x,y)=z and x=g(r,teta) and y=h(r,teta) and asks fxx. He solves this problem by...
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    What it exactly asks i this question?

    I am ging nearer but still some problems. I am lost between the x'(t),y'(t),x(t),y(t)... How should I get rid of this goddamn "t" ?:grumpy:
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