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bio website derek1906.site50.net
location United States, Hong Kong
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jQuery is taking over the world! http://i.stack.imgur.com/sGhaO.gif

function aboutMe(){
    var person = {
        name : "Derek",
        language : ["JavaScript", "Java", "PHP-some"],
        website : "http://derek1906.site50.net",
        use : function(){
            stayInStackOverflow(today);
        }
    }
    return person;
};

Hi there! I am the 283863 th user in stackoverflow.

Visit my website at:

(Actually both of them are the same.)


Dec
15
awarded  Caucus
Dec
13
comment Trisecting an angle
Nice, thanks.­­­­­
Dec
13
comment Trisecting an angle
@peterwhy - Oh by work I mean a good enough approximation... like how $y=x$ is a "good enough" approximation of $y=\sin{x}$ if $x$ is small.
Dec
13
comment Trisecting an angle
Thanks for this proof using contradiction! By the way, what program did you use to create this nice illustration?
Dec
13
accepted Trisecting an angle
Dec
13
comment Trisecting an angle
I see what you mean now. Since the distance from the middle point to the middle segment is way closer than the other two, the angle in between would be much greater than the other two, so this method only works for small angles. Thanks.
Dec
13
revised Trisecting an angle
added 66 characters in body
Dec
13
comment Trisecting an angle
They are almost "parallel", but they aren't. With great precision trisecting the angle is still possible with this method.
Dec
13
asked Trisecting an angle
Dec
4
comment Parametrizing intersection
@AmitaiYuval - Hm, thanks anyway.
Dec
4
comment Parametrizing intersection
@AmitaiYuval - It's graded by an online computer grader on those homework sites and it says that is not the correct answer.
Dec
4
revised Parametrizing intersection
added 85 characters in body
Dec
4
asked Parametrizing intersection
Nov
14
comment How to find the area inside $x^2+y^2+\sin(4x)+\sin(4y)=4$ using Green's Theorem
There's a thing called "change of coordinates" (in a single integral, this is called "u-substitution"), which by changing the coordinates system (surprise surprise), you can transform the shape to another shape that would be easier to parameterize and integrate. (Though I don't think it works in this case. You can try to change it into something similar to polar coordinates.)
Nov
14
comment How to find the area inside $x^2+y^2+\sin(4x)+\sin(4y)=4$ using Green's Theorem
(The hard part is parameterizing the curve.)
Nov
14
comment How to find the area inside $x^2+y^2+\sin(4x)+\sin(4y)=4$ using Green's Theorem
Green's Theorem is a theorem that relates a double integral to a single integral. To utilize the theorem on finding the area, first set up a double integral of $1$ over the bounded region D. From the theorem you can find that the area is equal to $\oint_{\partial D}x dy$, where $\partial D$ is the positively oriented boundary of the region D.
Nov
14
comment Parameterizing a surface
I see, parameterizations indeed are not unique.
Nov
14
accepted Parameterizing a surface
Nov
14
comment Parameterizing a surface
Wow, thank you for the detailed proof! Took me quite a while to read through it.
Nov
13
revised Parameterizing a surface
fixed small typo