Solution - Finding the roots of polynomials
Other Ways to Solve
Finding the roots of polynomialsStep by Step Solution
Step 1 :
6
Simplify —————
x - 2
Equation at the end of step 1 :
6 (((x3)-(6•(x2)))+11x)-——— x-2Step 2 :
Equation at the end of step 2 :
6
(((x3) - (2•3x2)) + 11x) - —————
x - 2
Step 3 :
Rewriting the whole as an Equivalent Fraction :
3.1 Subtracting a fraction from a whole
Rewrite the whole as a fraction using (x-2) as the denominator :
x3 - 6x2 + 11x (x3 - 6x2 + 11x) • (x - 2)
x3 - 6x2 + 11x = —————————————— = ——————————————————————————
1 (x - 2)
Equivalent fraction : The fraction thus generated looks different but has the same value as the whole
Common denominator : The equivalent fraction and the other fraction involved in the calculation share the same denominator
Step 4 :
Pulling out like terms :
4.1 Pull out like factors :
x3 - 6x2 + 11x = x • (x2 - 6x + 11)
Trying to factor by splitting the middle term
4.2 Factoring x2 - 6x + 11
The first term is, x2 its coefficient is 1 .
The middle term is, -6x its coefficient is -6 .
The last term, "the constant", is +11
Step-1 : Multiply the coefficient of the first term by the constant 1 • 11 = 11
Step-2 : Find two factors of 11 whose sum equals the coefficient of the middle term, which is -6 .
| -11 | + | -1 | = | -12 | ||
| -1 | + | -11 | = | -12 | ||
| 1 | + | 11 | = | 12 | ||
| 11 | + | 1 | = | 12 |
Observation : No two such factors can be found !!
Conclusion : Trinomial can not be factored
Adding fractions that have a common denominator :
4.3 Adding up the two equivalent fractions
Add the two equivalent fractions which now have a common denominator
Combine the numerators together, put the sum or difference over the common denominator then reduce to lowest terms if possible:
x • (x2-6x+11) • (x-2) - (6) x4 - 8x3 + 23x2 - 22x - 6
———————————————————————————— = —————————————————————————
1 • (x-2) 1 • (x - 2)
Polynomial Roots Calculator :
4.4 Find roots (zeroes) of : F(x) = x4 - 8x3 + 23x2 - 22x - 6
Polynomial Roots Calculator is a set of methods aimed at finding values of x for which F(x)=0
Rational Roots Test is one of the above mentioned tools. It would only find Rational Roots that is numbers x which can be expressed as the quotient of two integers
The Rational Root Theorem states that if a polynomial zeroes for a rational number P/Q then P is a factor of the Trailing Constant and Q is a factor of the Leading Coefficient
In this case, the Leading Coefficient is 1 and the Trailing Constant is -6.
The factor(s) are:
of the Leading Coefficient : 1
of the Trailing Constant : 1 ,2 ,3 ,6
Let us test ....
| P | Q | P/Q | F(P/Q) | Divisor | |||||
|---|---|---|---|---|---|---|---|---|---|
| -1 | 1 | -1.00 | 48.00 | ||||||
| -2 | 1 | -2.00 | 210.00 | ||||||
| -3 | 1 | -3.00 | 564.00 | ||||||
| -6 | 1 | -6.00 | 3978.00 | ||||||
| 1 | 1 | 1.00 | -12.00 | ||||||
| 2 | 1 | 2.00 | -6.00 | ||||||
| 3 | 1 | 3.00 | 0.00 | x - 3 | |||||
| 6 | 1 | 6.00 | 258.00 |
The Factor Theorem states that if P/Q is root of a polynomial then this polynomial can be divided by q*x-p Note that q and p originate from P/Q reduced to its lowest terms
In our case this means that
x4 - 8x3 + 23x2 - 22x - 6
can be divided with x - 3
Polynomial Long Division :
4.5 Polynomial Long Division
Dividing : x4 - 8x3 + 23x2 - 22x - 6
("Dividend")
By : x - 3 ("Divisor")
| dividend | x4 | - | 8x3 | + | 23x2 | - | 22x | - | 6 | ||
| - divisor | * x3 | x4 | - | 3x3 | |||||||
| remainder | - | 5x3 | + | 23x2 | - | 22x | - | 6 | |||
| - divisor | * -5x2 | - | 5x3 | + | 15x2 | ||||||
| remainder | 8x2 | - | 22x | - | 6 | ||||||
| - divisor | * 8x1 | 8x2 | - | 24x | |||||||
| remainder | 2x | - | 6 | ||||||||
| - divisor | * 2x0 | 2x | - | 6 | |||||||
| remainder | 0 |
Quotient : x3-5x2+8x+2 Remainder: 0
Polynomial Roots Calculator :
4.6 Find roots (zeroes) of : F(x) = x3-5x2+8x+2
See theory in step 4.4
In this case, the Leading Coefficient is 1 and the Trailing Constant is 2.
The factor(s) are:
of the Leading Coefficient : 1
of the Trailing Constant : 1 ,2
Let us test ....
| P | Q | P/Q | F(P/Q) | Divisor | |||||
|---|---|---|---|---|---|---|---|---|---|
| -1 | 1 | -1.00 | -12.00 | ||||||
| -2 | 1 | -2.00 | -42.00 | ||||||
| 1 | 1 | 1.00 | 6.00 | ||||||
| 2 | 1 | 2.00 | 6.00 |
Polynomial Roots Calculator found no rational roots
Final result :
(x3 - 5x2 + 8x + 2) • (x - 3)
—————————————————————————————
x - 2
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