Recent content by sedaw

thank you !

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: http://hyperphysics.phy-astr.gsu.edu/hbase/diverg.html

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

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

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...

attached herewith : the problem with my attempt to solve it .

F = dp/dt = d(mv)/dt = m(dv/dt) + v(dm/dt) = a + v(dm/dt) i don't understand why d(mv)/dt = m(dv/dt) + v(dm/dt) can someone help ? TNX !:smile:

ok tnx ...

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

hello ! need to find the volume of V: { x^2+y^2=z , x^4+y^4=1 } i don't 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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what next ? TNX !

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

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 !

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