MHB Real Solutions for a Complex System

  • Thread starter Thread starter anemone
  • Start date Start date
Click For Summary
The discussion centers on finding all real solutions for the equation $(x^2+3x+2)(x^2-2x-1)(x^2-7x+12)+24=0$. Participants acknowledge the complexity of the equation and express appreciation for contributions made by users like greg1313. The focus remains on solving the polynomial equation, with no additional unrelated topics introduced. The conversation highlights collaborative problem-solving in mathematics. Overall, the thread emphasizes the importance of community engagement in tackling complex mathematical challenges.
anemone
Gold Member
MHB
POTW Director
Messages
3,851
Reaction score
115
Solve for all real solutions for the system below:

$(x^2+3x+2)(x^2-2x-1)(x^2-7x+12)+24=0$
 
Mathematics news on Phys.org
anemone said:
Solve for all real solutions for the system below:

$(x^2+3x+2)(x^2-2x-1)(x^2-7x+12)+24=0$

$$(x^2+3x+2)(x^2-2x-1)(x^2-7x+12)+24$$

$$=x^6-6x^5+40x^3-13x^2-70x$$

$$=x(x^5-6x^4+40x^2-13x-70)$$

$$=x(x-2)(x^4-4x^3-8x^2+24x+35)$$

$$=x(x-2)(x^2-2x-5)(x^2-2x-7)=0$$

$$\implies x\in\left\{0,2,1\pm\sqrt6,1\pm2\sqrt2\right\}$$
 
greg1313 said:
$$(x^2+3x+2)(x^2-2x-1)(x^2-7x+12)+24$$

$$=x^6-6x^5+40x^3-13x^2-70x$$

$$=x(x^5-6x^4+40x^2-13x-70)$$

$$=x(x-2)(x^4-4x^3-8x^2+24x+35)$$

$$=x(x-2)(x^2-2x-5)(x^2-2x-7)=0$$

$$\implies x\in\left\{0,2,1\pm\sqrt6,1\pm2\sqrt2\right\}$$

Sorry greg1313 for the late reply!

Very well done greg1313! And thanks for participating!
 
Thread 'Erroneously  finding discrepancy in transpose rule'
Obviously, there is something elementary I am missing here. To form the transpose of a matrix, one exchanges rows and columns, so the transpose of a scalar, considered as (or isomorphic to) a one-entry matrix, should stay the same, including if the scalar is a complex number. On the other hand, in the isomorphism between the complex plane and the real plane, a complex number a+bi corresponds to a matrix in the real plane; taking the transpose we get which then corresponds to a-bi...

Similar threads

  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 7 ·
Replies
7
Views
1K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 13 ·
Replies
13
Views
2K
Replies
11
Views
1K
Replies
48
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K