6x^2 + (sqrt(3) - 13)x +3 + sqrt(3) = 0
2007-01-09
23:40:36
·
10 answers
·
asked by
kirokamata
1
in
Science & Mathematics
➔ Mathematics
Well, folks, the point in that problem is that I should keep the squire roots and use the properties of the roots.
When I estimate the D, I find, that it is 100- 50*sqrt(3), but I cannot put that under a sq root.
2007-01-09
23:52:35 ·
update #1
.
This is jus another quadratic equation... The co-efficients are jus irrational... Nevertheless, this equation gives 2 perfectly real roots...
The 2 roots are:
1.7090853153992358558683710732327
0.168906216672617928543721203182
.
2007-01-10 00:17:43
·
answer #1
·
answered by Preety 2
·
0⤊
0⤋
No problem. So you end up with :
x = {13 - sqrt(3) ± sqrt[100 - 50*sqrt(3)]} / 12
Let's look at sqrt[100 - 50*sqrt(3)].
Taking out the factor 25, this becomes :
sqrt{25[4 - 2*sqrt(3)]}, which is 5*sqrt[4 - 2*sqrt(3)].
Now let's look at sqrt[4 - 2*sqrt(3)].
Assume that sqrt[4 - 2*sqrt(3)] = sqrt(a) - sqrt(b).
Squaring both sides gives :
4 - 2*sqrt(3) = a + b - 2*sqrt(ab)
Equating rationals and irrationals gives :
4 = a + b
3 = ab
So, b = 4 - a.
Plug this into 3 = ab to get 3 = a(4 - a)
Rearranging gives : a^2 - 4a + 3 = 0
Factorising gives : (a - 3)(a - 1) = 0
Thus, a = 3 or 1, so, b = 1 or 3.
It doesn't matter which is which,
but we'll take a = 3 and b = 1,
so that we get positive values for the equation.
Therefore, sqrt[4 - 2*sqrt(3)] = sqrt(3) - 1
Now, x will be {13 - sqrt(3) ± 5[sqrt(3) - 1)] / 12
Now we can add them.
Thus, x = [2 + sqrt(3)] / 3 or x = [3 - sqrt(3)] / 2.
I haven't tested these by plugging them back
into the equation, so I'll leave that for you.
2007-01-10 00:45:25
·
answer #2
·
answered by falzoon 7
·
0⤊
0⤋
The QuadraticFormula is used to solve equations like:
a x^2 + b x + c = 0 .
It gives the possible values for x in terms of a, b, and c. You can derive it by completing the square; the result is this:
If a x^2 + b x + c = 0 then either
- b + sqrt( b^2 - 4 a c )
x = --------------------------- or
2 a
- b - sqrt( b^2 - 4 a c )
x = ---------------------------
2 a
2007-01-09 23:59:10
·
answer #3
·
answered by runlolarun 4
·
0⤊
0⤋
6x^2 + (sqrt(3) - 13)x +3 + sqrt(3) = 0
6x^2 + sqrt(3)x - 13x +3 + sqrt(3) = 0
6x^2 + sqrt(3)x - 13x +3 + sqrt(3) = 0
x(6x + sqrt(3) -13) +3 + sqrt(3) = 0
hell i give up...too tired
2007-01-09 23:45:01
·
answer #4
·
answered by Dashes 6
·
0⤊
1⤋
use discrete methode
i.e.
d=b^2-4ac and d=0 for real roots
a,b,c are
ax^2+bx+c=0
for any quadratic equation
2007-01-09 23:50:17
·
answer #5
·
answered by puneet k 1
·
0⤊
0⤋
it is a quadratic equation, u can use completing square method or use the quadratic formula, you can get two roots i think!
2007-01-09 23:48:42
·
answer #6
·
answered by flongkoy 2
·
0⤊
0⤋
How much wood would a woodchuck chuck if a woodchuck could chuck wood?
2007-01-09 23:45:15
·
answer #7
·
answered by TryingToLearn 2
·
0⤊
1⤋
You need to do your own homework honey -- that's how you learn!
2007-01-09 23:43:10
·
answer #8
·
answered by kja63 7
·
0⤊
0⤋
x=x
2007-01-09 23:42:53
·
answer #9
·
answered by trey64op 2
·
0⤊
0⤋
.63397 or 1.244
2007-01-09 23:53:14
·
answer #10
·
answered by crazylikepig 1
·
0⤊
0⤋