Solution - Finding the roots of polynomials
Other Ways to Solve
Finding the roots of polynomialsStep by Step Solution
Step 1 :
12
Simplify ——
a2
Equation at the end of step 1 :
12
((((a2) + 11a) - ——) - 2a) + 3
a2
Step 2 :
Rewriting the whole as an Equivalent Fraction :
2.1 Subtracting a fraction from a whole
Rewrite the whole as a fraction using a2 as the denominator :
a2 + 11a (a2 + 11a) • a2
a2 + 11a = ———————— = ———————————————
1 a2
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 3 :
Pulling out like terms :
3.1 Pull out like factors :
a2 + 11a = a • (a + 11)
Adding fractions that have a common denominator :
3.2 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:
a • (a+11) • a2 - (12) a4 + 11a3 - 12
—————————————————————— = ——————————————
a2 a2
Equation at the end of step 3 :
(a4 + 11a3 - 12)
(———————————————— - 2a) + 3
a2
Step 4 :
Rewriting the whole as an Equivalent Fraction :
4.1 Subtracting a whole from a fraction
Rewrite the whole as a fraction using a2 as the denominator :
2a 2a • a2
2a = —— = ———————
1 a2
Polynomial Roots Calculator :
4.2 Find roots (zeroes) of : F(a) = a4 + 11a3 - 12
Polynomial Roots Calculator is a set of methods aimed at finding values of a for which F(a)=0
Rational Roots Test is one of the above mentioned tools. It would only find Rational Roots that is numbers a 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 -12.
The factor(s) are:
of the Leading Coefficient : 1
of the Trailing Constant : 1 ,2 ,3 ,4 ,6 ,12
Let us test ....
P | Q | P/Q | F(P/Q) | Divisor | |||||
---|---|---|---|---|---|---|---|---|---|
-1 | 1 | -1.00 | -22.00 | ||||||
-2 | 1 | -2.00 | -84.00 | ||||||
-3 | 1 | -3.00 | -228.00 | ||||||
-4 | 1 | -4.00 | -460.00 | ||||||
-6 | 1 | -6.00 | -1092.00 | ||||||
-12 | 1 | -12.00 | 1716.00 | ||||||
1 | 1 | 1.00 | 0.00 | a - 1 | |||||
2 | 1 | 2.00 | 92.00 | ||||||
3 | 1 | 3.00 | 366.00 | ||||||
4 | 1 | 4.00 | 948.00 | ||||||
6 | 1 | 6.00 | 3660.00 | ||||||
12 | 1 | 12.00 | 39732.00 |
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
a4 + 11a3 - 12
can be divided with a - 1
Polynomial Long Division :
4.3 Polynomial Long Division
Dividing : a4 + 11a3 - 12
("Dividend")
By : a - 1 ("Divisor")
dividend | a4 | + | 11a3 | - | 12 | ||||||
- divisor | * a3 | a4 | - | a3 | |||||||
remainder | 12a3 | - | 12 | ||||||||
- divisor | * 12a2 | 12a3 | - | 12a2 | |||||||
remainder | 12a2 | - | 12 | ||||||||
- divisor | * 12a1 | 12a2 | - | 12a | |||||||
remainder | 12a | - | 12 | ||||||||
- divisor | * 12a0 | 12a | - | 12 | |||||||
remainder | 0 |
Quotient : a3+12a2+12a+12 Remainder: 0
Polynomial Roots Calculator :
4.4 Find roots (zeroes) of : F(a) = a3+12a2+12a+12
See theory in step 4.2
In this case, the Leading Coefficient is 1 and the Trailing Constant is 12.
The factor(s) are:
of the Leading Coefficient : 1
of the Trailing Constant : 1 ,2 ,3 ,4 ,6 ,12
Let us test ....
P | Q | P/Q | F(P/Q) | Divisor | |||||
---|---|---|---|---|---|---|---|---|---|
-1 | 1 | -1.00 | 11.00 | ||||||
-2 | 1 | -2.00 | 28.00 | ||||||
-3 | 1 | -3.00 | 57.00 | ||||||
-4 | 1 | -4.00 | 92.00 | ||||||
-6 | 1 | -6.00 | 156.00 | ||||||
-12 | 1 | -12.00 | -132.00 | ||||||
1 | 1 | 1.00 | 37.00 | ||||||
2 | 1 | 2.00 | 92.00 | ||||||
3 | 1 | 3.00 | 183.00 | ||||||
4 | 1 | 4.00 | 316.00 | ||||||
6 | 1 | 6.00 | 732.00 | ||||||
12 | 1 | 12.00 | 3612.00 |
Polynomial Roots Calculator found no rational roots
Adding fractions that have a common denominator :
4.5 Adding up the two equivalent fractions
(a3+12a2+12a+12) • (a-1) - (2a • a2) a4 + 9a3 - 12
———————————————————————————————————— = —————————————
a2 a2
Equation at the end of step 4 :
(a4 + 9a3 - 12)
——————————————— + 3
a2
Step 5 :
Rewriting the whole as an Equivalent Fraction :
5.1 Adding a whole to a fraction
Rewrite the whole as a fraction using a2 as the denominator :
3 3 • a2
3 = — = ——————
1 a2
Polynomial Roots Calculator :
5.2 Find roots (zeroes) of : F(a) = a4 + 9a3 - 12
See theory in step 4.2
In this case, the Leading Coefficient is 1 and the Trailing Constant is -12.
The factor(s) are:
of the Leading Coefficient : 1
of the Trailing Constant : 1 ,2 ,3 ,4 ,6 ,12
Let us test ....
P | Q | P/Q | F(P/Q) | Divisor | |||||
---|---|---|---|---|---|---|---|---|---|
-1 | 1 | -1.00 | -20.00 | ||||||
-2 | 1 | -2.00 | -68.00 | ||||||
-3 | 1 | -3.00 | -174.00 | ||||||
-4 | 1 | -4.00 | -332.00 | ||||||
-6 | 1 | -6.00 | -660.00 | ||||||
-12 | 1 | -12.00 | 5172.00 | ||||||
1 | 1 | 1.00 | -2.00 | ||||||
2 | 1 | 2.00 | 76.00 | ||||||
3 | 1 | 3.00 | 312.00 | ||||||
4 | 1 | 4.00 | 820.00 | ||||||
6 | 1 | 6.00 | 3228.00 | ||||||
12 | 1 | 12.00 | 36276.00 |
Polynomial Roots Calculator found no rational roots
Adding fractions that have a common denominator :
5.3 Adding up the two equivalent fractions
(a4+9a3-12) + 3 • a2 a4 + 9a3 + 3a2 - 12
———————————————————— = ———————————————————
a2 a2
Checking for a perfect cube :
5.4 a4 + 9a3 + 3a2 - 12 is not a perfect cube
Trying to factor by pulling out :
5.5 Factoring: a4 + 9a3 + 3a2 - 12
Thoughtfully split the expression at hand into groups, each group having two terms :
Group 1: 3a2 - 12
Group 2: 9a3 + a4
Pull out from each group separately :
Group 1: (a2 - 4) • (3)
Group 2: (a + 9) • (a3)
Bad news !! Factoring by pulling out fails :
The groups have no common factor and can not be added up to form a multiplication.
Polynomial Roots Calculator :
5.6 Find roots (zeroes) of : F(a) = a4 + 9a3 + 3a2 - 12
See theory in step 4.2
In this case, the Leading Coefficient is 1 and the Trailing Constant is -12.
The factor(s) are:
of the Leading Coefficient : 1
of the Trailing Constant : 1 ,2 ,3 ,4 ,6 ,12
Let us test ....
P | Q | P/Q | F(P/Q) | Divisor | |||||
---|---|---|---|---|---|---|---|---|---|
-1 | 1 | -1.00 | -17.00 | ||||||
-2 | 1 | -2.00 | -56.00 | ||||||
-3 | 1 | -3.00 | -147.00 | ||||||
-4 | 1 | -4.00 | -284.00 | ||||||
-6 | 1 | -6.00 | -552.00 | ||||||
-12 | 1 | -12.00 | 5604.00 | ||||||
1 | 1 | 1.00 | 1.00 | ||||||
2 | 1 | 2.00 | 88.00 | ||||||
3 | 1 | 3.00 | 339.00 | ||||||
4 | 1 | 4.00 | 868.00 | ||||||
6 | 1 | 6.00 | 3336.00 | ||||||
12 | 1 | 12.00 | 36708.00 |
Polynomial Roots Calculator found no rational roots
Final result :
a4 + 9a3 + 3a2 - 12
———————————————————
a2
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