Recent content by sedaw

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    Divergence operator in cylindrical & sherical

    look for some proof for the formula of the divergence operator in cylindrical & spherical coordinate is there any on the net ? TNX ! the formula here:
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    Negative volume ?

    negative volume ??? attached herewith pdf file with the problem and my solution .
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    Need help volume calculation .

    ok.. thank you very much i am appreciate your help. by the way my picture is V for the uvz axis and not xyz .
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    Need help volume calculation .

    cotan(t) = cos(t)/sit(t) the limits of integration on u & v simply received from the projection of the region bounded by V on the UV plane -> you can see it circle with radius R=1 . the limits of integration on z: you can see in sketch : 0<=z<=U+V (of course just for u & v that in...
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    Need help volume calculation .

    attached herewith : the problem with my attempt to solve it .
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    The generalization of Newton's 2nd Law to apply to variable mass systems

    F = dp/dt = d(mv)/dt = m(dv/dt) + v(dm/dt) = a + v(dm/dt) i dont understand why d(mv)/dt = m(dv/dt) + v(dm/dt) can somone help ? TNX !:smile:
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    Limit problem calculate

    need to calculate lim X->infinity of x*[1/x] , while [] represent floor function . TNX.
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    Volume problem

    hello ! need to find the volume of V: { x^2+y^2=z , x^4+y^4=1 } i dont know how to set up the triple integral caue i didnt find any way to understand the surface projection on the xy plane . I would appreciate any help ....
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    Problem with integrating factor

    what next ? TNX !
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    Calculate the limit of the series

    hello Dick ! first of all tnx. i cant use l'Hopital's theorem cause n =1,2,3..... so F(n) not differentiable .
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    Calculate the limit of the series

    need to calculate the limit of the series (cos(a/n))^(n^3) n goes to infinity and a=!0 i try that : e^L L= the limit of (n^3)*ln(cos(a/n)) what now ??? TNX !
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    Sum of 1/ln(n)^(ln(n)) from n=3 to infinity?

    nope , you are magician , how u did it ? TNX !