Solution - Polynomial long division
Other Ways to Solve
Polynomial long divisionStep by Step Solution
Step 1 :
1
Simplify ————————
(s - 2)5
Equation at the end of step 1 :
1
l - (1 • ————————)
(s - 2)5
Step 2 :
Equation at the end of step 2 :
1
l - ————————
(s - 2)5
Step 3 :
Rewriting the whole as an Equivalent Fraction :
3.1 Subtracting a fraction from a whole
Rewrite the whole as a fraction using (s-2)5 as the denominator :
l l • (s - 2)5
l = — = ————————————
1 (s - 2)5
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
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:
l • (s-2)5 - (1) ls5 - 10ls4 + 40ls3 - 80ls2 + 80ls - 32l - 1
———————————————— = ————————————————————————————————————————————
1 • (s-2)5 1 • (s5 - 10s4 + 40s3 - 80s2 + 80s - 32)
Trying to factor by pulling out :
3.3 Factoring: s5 - 10s4 + 40s3 - 80s2 + 80s - 32
Thoughtfully split the expression at hand into groups, each group having two terms :
Group 1: -10s4 + s5
Group 2: -80s2 + 40s3
Group 3: 80s - 32
Pull out from each group separately :
Group 1: (s - 10) • (s4)
Group 2: (s - 2) • (40s2)
Group 3: (5s - 2) • (16)
Looking for common sub-expressions :
Group 1: (s - 10) • (s4)
Group 3: (5s - 2) • (16)
Group 2: (s - 2) • (40s2)
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 :
3.4 Find roots (zeroes) of : F(s) = s5 - 10s4 + 40s3 - 80s2 + 80s - 32
Polynomial Roots Calculator is a set of methods aimed at finding values of s for which F(s)=0
Rational Roots Test is one of the above mentioned tools. It would only find Rational Roots that is numbers s 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 -32.
The factor(s) are:
of the Leading Coefficient : 1
of the Trailing Constant : 1 ,2 ,4 ,8 ,16 ,32
Let us test ....
P | Q | P/Q | F(P/Q) | Divisor | |||||
---|---|---|---|---|---|---|---|---|---|
-1 | 1 | -1.00 | -243.00 | ||||||
-2 | 1 | -2.00 | -1024.00 | ||||||
-4 | 1 | -4.00 | -7776.00 | ||||||
-8 | 1 | -8.00 | -100000.00 | ||||||
-16 | 1 | -16.00 | -1889568.00 | ||||||
-32 | 1 | -32.00 | -45435424.00 | ||||||
1 | 1 | 1.00 | -1.00 | ||||||
2 | 1 | 2.00 | 0.00 | s - 2 | |||||
4 | 1 | 4.00 | 32.00 | ||||||
8 | 1 | 8.00 | 7776.00 | ||||||
16 | 1 | 16.00 | 537824.00 | ||||||
32 | 1 | 32.00 | 24300000.00 |
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
s5 - 10s4 + 40s3 - 80s2 + 80s - 32
can be divided with s - 2
Polynomial Long Division :
3.5 Polynomial Long Division
Dividing : s5 - 10s4 + 40s3 - 80s2 + 80s - 32
("Dividend")
By : s - 2 ("Divisor")
dividend | s5 | - | 10s4 | + | 40s3 | - | 80s2 | + | 80s | - | 32 | ||
- divisor | * s4 | s5 | - | 2s4 | |||||||||
remainder | - | 8s4 | + | 40s3 | - | 80s2 | + | 80s | - | 32 | |||
- divisor | * -8s3 | - | 8s4 | + | 16s3 | ||||||||
remainder | 24s3 | - | 80s2 | + | 80s | - | 32 | ||||||
- divisor | * 24s2 | 24s3 | - | 48s2 | |||||||||
remainder | - | 32s2 | + | 80s | - | 32 | |||||||
- divisor | * -32s1 | - | 32s2 | + | 64s | ||||||||
remainder | 16s | - | 32 | ||||||||||
- divisor | * 16s0 | 16s | - | 32 | |||||||||
remainder | 0 |
Quotient : s4-8s3+24s2-32s+16 Remainder: 0
Polynomial Roots Calculator :
3.6 Find roots (zeroes) of : F(s) = s4-8s3+24s2-32s+16
See theory in step 3.4
In this case, the Leading Coefficient is 1 and the Trailing Constant is 16.
The factor(s) are:
of the Leading Coefficient : 1
of the Trailing Constant : 1 ,2 ,4 ,8 ,16
Let us test ....
P | Q | P/Q | F(P/Q) | Divisor | |||||
---|---|---|---|---|---|---|---|---|---|
-1 | 1 | -1.00 | 81.00 | ||||||
-2 | 1 | -2.00 | 256.00 | ||||||
-4 | 1 | -4.00 | 1296.00 | ||||||
-8 | 1 | -8.00 | 10000.00 | ||||||
-16 | 1 | -16.00 | 104976.00 | ||||||
1 | 1 | 1.00 | 1.00 | ||||||
2 | 1 | 2.00 | 0.00 | s-2 | |||||
4 | 1 | 4.00 | 16.00 | ||||||
8 | 1 | 8.00 | 1296.00 | ||||||
16 | 1 | 16.00 | 38416.00 |
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
s4-8s3+24s2-32s+16
can be divided with s-2
Polynomial Long Division :
3.7 Polynomial Long Division
Dividing : s4-8s3+24s2-32s+16
("Dividend")
By : s-2 ("Divisor")
dividend | s4 | - | 8s3 | + | 24s2 | - | 32s | + | 16 | ||
- divisor | * s3 | s4 | - | 2s3 | |||||||
remainder | - | 6s3 | + | 24s2 | - | 32s | + | 16 | |||
- divisor | * -6s2 | - | 6s3 | + | 12s2 | ||||||
remainder | 12s2 | - | 32s | + | 16 | ||||||
- divisor | * 12s1 | 12s2 | - | 24s | |||||||
remainder | - | 8s | + | 16 | |||||||
- divisor | * -8s0 | - | 8s | + | 16 | ||||||
remainder | 0 |
Quotient : s3-6s2+12s-8 Remainder: 0
Polynomial Roots Calculator :
3.8 Find roots (zeroes) of : F(s) = s3-6s2+12s-8
See theory in step 3.4
In this case, the Leading Coefficient is 1 and the Trailing Constant is -8.
The factor(s) are:
of the Leading Coefficient : 1
of the Trailing Constant : 1 ,2 ,4 ,8
Let us test ....
P | Q | P/Q | F(P/Q) | Divisor | |||||
---|---|---|---|---|---|---|---|---|---|
-1 | 1 | -1.00 | -27.00 | ||||||
-2 | 1 | -2.00 | -64.00 | ||||||
-4 | 1 | -4.00 | -216.00 | ||||||
-8 | 1 | -8.00 | -1000.00 | ||||||
1 | 1 | 1.00 | -1.00 | ||||||
2 | 1 | 2.00 | 0.00 | s-2 | |||||
4 | 1 | 4.00 | 8.00 | ||||||
8 | 1 | 8.00 | 216.00 |
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
s3-6s2+12s-8
can be divided with s-2
Polynomial Long Division :
3.9 Polynomial Long Division
Dividing : s3-6s2+12s-8
("Dividend")
By : s-2 ("Divisor")
dividend | s3 | - | 6s2 | + | 12s | - | 8 | ||
- divisor | * s2 | s3 | - | 2s2 | |||||
remainder | - | 4s2 | + | 12s | - | 8 | |||
- divisor | * -4s1 | - | 4s2 | + | 8s | ||||
remainder | 4s | - | 8 | ||||||
- divisor | * 4s0 | 4s | - | 8 | |||||
remainder | 0 |
Quotient : s2-4s+4 Remainder: 0
Trying to factor by splitting the middle term
3.10 Factoring s2-4s+4
The first term is, s2 its coefficient is 1 .
The middle term is, -4s its coefficient is -4 .
The last term, "the constant", is +4
Step-1 : Multiply the coefficient of the first term by the constant 1 • 4 = 4
Step-2 : Find two factors of 4 whose sum equals the coefficient of the middle term, which is -4 .
-4 | + | -1 | = | -5 | ||
-2 | + | -2 | = | -4 | That's it |
Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, -2 and -2
s2 - 2s - 2s - 4
Step-4 : Add up the first 2 terms, pulling out like factors :
s • (s-2)
Add up the last 2 terms, pulling out common factors :
2 • (s-2)
Step-5 : Add up the four terms of step 4 :
(s-2) • (s-2)
Which is the desired factorization
Multiplying Exponential Expressions :
3.11 Multiply (s-2) by (s-2)
The rule says : To multiply exponential expressions which have the same base, add up their exponents.
In our case, the common base is (s-2) and the exponents are :
1 , as (s-2) is the same number as (s-2)1
and 1 , as (s-2) is the same number as (s-2)1
The product is therefore, (s-2)(1+1) = (s-2)2
Multiplying Exponential Expressions :
3.12 Multiply (s-2)2 by (s-2)
The rule says : To multiply exponential expressions which have the same base, add up their exponents.
In our case, the common base is (s-2) and the exponents are :
2
and 1 , as (s-2) is the same number as (s-2)1
The product is therefore, (s-2)(2+1) = (s-2)3
Multiplying Exponential Expressions :
3.13 Multiply (s-2)3 by (s-2)
The rule says : To multiply exponential expressions which have the same base, add up their exponents.
In our case, the common base is (s-2) and the exponents are :
3
and 1 , as (s-2) is the same number as (s-2)1
The product is therefore, (s-2)(3+1) = (s-2)4
Multiplying Exponential Expressions :
3.14 Multiply (s-2)4 by (s-2)
The rule says : To multiply exponential expressions which have the same base, add up their exponents.
In our case, the common base is (s-2) and the exponents are :
4
and 1 , as (s-2) is the same number as (s-2)1
The product is therefore, (s-2)(4+1) = (s-2)5
Final result :
ls5 - 10ls4 + 40ls3 - 80ls2 + 80ls - 32l - 1
————————————————————————————————————————————
(s - 2)5
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