Recent content by kelvintc

oh .. thanks a lot ... :)

oh ... thanks... p/s : (1) what's Newton method? (2) find intercepts between trig and non-vertical/non-horizontal functions ? i not yet learn both also and my textbook is doesnot contain Newton's method also.. i will try to find it out... my friend told me use 'trials and errors'...

10 sin x = -x can anyone give me tips how to solve this equation? i run out of ideas even to transform this equation to another form.. sigh sigh thanks...

anyone can help me on these magnetostatic problems? I'm stucked ..

cannot use Latex code anymore?

1) Calculate the self-inductance of a coaxial cable of inner radius a and outer radius b. The inner conductor is made of an inhomogenous material having u = 2u0/(1+r) Answer : u0L/8pie + u0L/pie (ln(b/a) - ln((1+b)/(1+a))) 2) Two #10 copper wires(2.588 mm in diameter) are placed parallel...

i had been doing these qs over the past few weeks and there are still some questions remained unsolved.. anyone can help ? q3, 7, 8, 9, 13, 14, 15

ya... i did it like that

i got 4 for z=0 to z=2 for (z^2-1) then integrate get 2pie x r since r=2 then 4 times 4pie get 16pie

i think i got the answer for (6). just not sure whether the method is wrong or not

(1) a_{r} = \cos{\phi}{a}_{x} + \sin{\phi}{a}_{y} a_{\phi} = -\sin{\phi}{a}_{x} + \cos{\phi}{a}_{y} a_{z} = a_{z} then z=0, so vector in x direction only depends on phi . -e^{-2}\sin\frac{\phi}{2}\sin\phi=-0.0586

replace z=0 and z=2 to get (z^2-1) ? then find \int{rd\phi}{dr} ? by this i get 16\pi... i also get the surface integral in r direction = 0

thanks again.. hehe... oh... i really made too much mistakes in calculation.. sad

no.6 i translate all x,y,z into cylindrical coordinates. x = r\cos\phi y = r\sin\phi z = z a_{x} = \cos{\phi}{a}_{r} - \sin{\phi}{a}_{\phi} a_{y} = \sin{\phi}{a}_{r} + \cos{\phi}{a}_{\phi} a_{x} = a_{z} dS = rd\phi{d}{r}a_{r} Hence, F_{r} = r^2\cos^3\phi + r^2\sin^3\phi integrate i...

about (1) since z=0, a_{r} has no a_{x} component , a_{\phi} = -\sin{\phi}{a}_{x} + \cos{\phi}{a}_{y} e^{-2}\sin\frac{\phi}{2}*-\sin\phi=-0.102