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Mathematics 19 Online
OpenStudy (solomonzelman):

Don't troll me, I know I suck at math. ATTEMPT NUMBER 6: \(\huge\color{blue}{\huge {\bbox[5pt,cyan,border:2px solid purple]{f(x)=x^3+x+1}}}\)

OpenStudy (solomonzelman):

\(\huge\color{blue}{\huge {\bbox[5pt,cyan,border:2px solid purple]{PLEASE~~~~EXPLAIN}}}\) \(\huge\color{blue}{\huge {\bbox[5pt,cyan,border:2px solid purple]{How~~do~~I~~find~~the~~roots?}}}\)

OpenStudy (anonymous):

kk

OpenStudy (221emily):

sorry I suck at math also

OpenStudy (gatorgirl):

Sorry, that's too advanced for me and I suck at math too.

OpenStudy (travisbrown372):

no idea

OpenStudy (btaylor):

You find roots by setting it equal to zero. This is tricky to factor, since it is x^3. It actually doesn't factor. But if you graph it and find the x-intercept (the zero/root), you will find x=-.68233

OpenStudy (solomonzelman):

So I can only approximately find the roots, I can never actually find the roots for sure, like an exact value (sqrt5 -4i or integer or something like that)? It will depend on how accurately will I graph it?

OpenStudy (ikram002p):

can u use approximation ??

OpenStudy (ikram002p):

there is no intrger sol for sure but u can a proximate..

OpenStudy (solomonzelman):

approximation? I was never good at mathematical terms, what do you mean, perhaps I might know. Also, is there an exact answer to the problem?

OpenStudy (solomonzelman):

May it be -5i or sqrt4+3i or anything, but exact value.

OpenStudy (ikram002p):

it might have an exact sol but not integer

OpenStudy (ikram002p):

yeb it could be complex or irrational

OpenStudy (solomonzelman):

Whatever the exact value is, how do you find it?

OpenStudy (ikram002p):

ok do u know kardano method ??

OpenStudy (solomonzelman):

No, but I think ganeshie8 showed to me, I don't remember the formula, and I've never done it. It would be pretty difficult to teach me, being that I know nearly nothing.

OpenStudy (ikram002p):

its for x^3=px+q \[x=\sqrt[3]{\frac{ q }{ 2 }+\sqrt{\frac{ q^2 }{ 4 }-\frac{ p^3 }{ 27 }}}+x=\sqrt[3]{\frac{ q }{ 2 }-\sqrt{\frac{ q^2 }{ 4 }-\frac{ p^3 }{ 27 }}}\]

OpenStudy (ikram002p):

ok gust apply the formula and ul get a sol :)

OpenStudy (ikram002p):

oh i type it rongly sry ..

OpenStudy (solomonzelman):

i need time to calculate it....

OpenStudy (solomonzelman):

rongly?

OpenStudy (ikram002p):

\[x=\sqrt[3]{\frac{ q }{ 2 }+\sqrt{\frac{ q^2 }{ 4 }-\frac{ p^3 }{ 27 }}}+\sqrt[3]{\frac{ q }{ 2 }-\sqrt{\frac{ q^2 }{ 4 }-\frac{ p^3 }{ 27 }}}\]

OpenStudy (solomonzelman):

oh, w/o x=

OpenStudy (ikram002p):

take ur time its oly calculating =)

OpenStudy (ikram002p):

p=-1 q=-1

OpenStudy (solomonzelman):

What? I though it's +1 and +1

OpenStudy (ikram002p):

x^3=px+q ur equation is x^3+x+1 so x^3=-x-1 q=-1 p=-1

OpenStudy (solomonzelman):

I'll be back, 2 minutes...

OpenStudy (anonymous):

A plot and solution using Mathematica 8 Home Edition is attached.

OpenStudy (anonymous):

Sorry, there are two mis-spellings in solomonzelman.pdf

undeadknight26 (undeadknight26):

Lol u say u suck at math when i think ur like a math teacher...

OpenStudy (anonymous):

SO to find a root of this function all you're trying to do is find where the graph hits zero

OpenStudy (shamil98):

How does one write in such cool latex O_O

OpenStudy (solomonzelman):

thank you, my latex aren't cool..... anyway, http://openstudy.com/study#/updates/51fbcbade4b0cc46c14a461d

OpenStudy (solomonzelman):

I just combined them.

OpenStudy (solomonzelman):

\(\huge\color{magenta}{\huge {\bbox[5pt,yellow ,border:2px solid blue ]{~•~~‿~•~}}}\)

OpenStudy (agent0smith):

http://www.wolframalpha.com/input/?i=x%5E3%2Bx%2B1%3D0 you can click exact forms. They are very ugly.

OpenStudy (solomonzelman):

it's +31, not just 1.

OpenStudy (solomonzelman):

I see, but how does he get it?

OpenStudy (wolf1728):

What does shamil 98 mean by writing in cool latex?

OpenStudy (solomonzelman):

Idk, he thought my latex were cool perhaps, but they're not.

OpenStudy (agent0smith):

"it's +31, not just 1." no it isn't, in your first post.

OpenStudy (solomonzelman):

\(\Huge{\color{purple}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{cyan}{\bigstar}\color{purple}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{cyan}{\bigstar}\color{purple}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}}\\\color{white}{.}\\\Huge\sf\color{magenta }{~~f(x)=x^3+x+31~\\}\\\color{white}{.}\\\\\Huge{\color{purple}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{cyan}{\bigstar}\color{purple}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{cyan}{\bigstar}\color{purple}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}}\)

OpenStudy (agent0smith):

http://www.wolframalpha.com/input/?i=x%5E3%2Bx%2B31%3D0

OpenStudy (solomonzelman):

I re-inputted (if that makes sense) and I see the answer, but I need to know how to do it.

OpenStudy (solomonzelman):

I am going to play basketball right now, thank for trying to help everyone! It's waiting for me!!!!!!!!!!!!!! \(\Huge{\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{orange}{\bigstar}\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{orange}{\bigstar}\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}}\\\color{white}{.}\\\Huge\sf\color{blue}{~~~~Have~~~a~~~good~~~night!~\\}\\\color{white}{.}\\\\\Huge{\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{orange}{\bigstar}\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{orange}{\bigstar}\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}}\)

OpenStudy (dumbcow):

if you look at the steps for exact solution in wolfram it breaks down how to do it it uses a variable transformation then back substitution

OpenStudy (dumbcow):

normally when no rational zero exists , approximation from calculator suffice or if you know calculus , Newtons method is great for finding irrational zeros

OpenStudy (solomonzelman):

Yeah, I kind of got it.

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