How to separate an equation into partial fractions?
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I am looking at a math question that has simplified this:

into this:

Can somebody explain the process for how this simplification was made? i.e. how does the denominator get broken down to those two terms?
partial-fractions
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add a comment |
$begingroup$
I am looking at a math question that has simplified this:

into this:

Can somebody explain the process for how this simplification was made? i.e. how does the denominator get broken down to those two terms?
partial-fractions
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1
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Numerator $1=y+1-y$
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– lab bhattacharjee
Dec 27 '18 at 4:13
1
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This can be done with partial fraction decomposition. en.wikipedia.org/wiki/Partial_fraction_decomposition
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– CyclotomicField
Dec 27 '18 at 4:14
add a comment |
$begingroup$
I am looking at a math question that has simplified this:

into this:

Can somebody explain the process for how this simplification was made? i.e. how does the denominator get broken down to those two terms?
partial-fractions
$endgroup$
I am looking at a math question that has simplified this:

into this:

Can somebody explain the process for how this simplification was made? i.e. how does the denominator get broken down to those two terms?
partial-fractions
partial-fractions
asked Dec 27 '18 at 4:11
StartecStartec
1236
1236
1
$begingroup$
Numerator $1=y+1-y$
$endgroup$
– lab bhattacharjee
Dec 27 '18 at 4:13
1
$begingroup$
This can be done with partial fraction decomposition. en.wikipedia.org/wiki/Partial_fraction_decomposition
$endgroup$
– CyclotomicField
Dec 27 '18 at 4:14
add a comment |
1
$begingroup$
Numerator $1=y+1-y$
$endgroup$
– lab bhattacharjee
Dec 27 '18 at 4:13
1
$begingroup$
This can be done with partial fraction decomposition. en.wikipedia.org/wiki/Partial_fraction_decomposition
$endgroup$
– CyclotomicField
Dec 27 '18 at 4:14
1
1
$begingroup$
Numerator $1=y+1-y$
$endgroup$
– lab bhattacharjee
Dec 27 '18 at 4:13
$begingroup$
Numerator $1=y+1-y$
$endgroup$
– lab bhattacharjee
Dec 27 '18 at 4:13
1
1
$begingroup$
This can be done with partial fraction decomposition. en.wikipedia.org/wiki/Partial_fraction_decomposition
$endgroup$
– CyclotomicField
Dec 27 '18 at 4:14
$begingroup$
This can be done with partial fraction decomposition. en.wikipedia.org/wiki/Partial_fraction_decomposition
$endgroup$
– CyclotomicField
Dec 27 '18 at 4:14
add a comment |
2 Answers
2
active
oldest
votes
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Here's a quick and easy way for simple or basic fractions$$frac 1{y(1-y)}=frac {color{blue}{1-y}+y}{y(color{blue}{1-y})}=frac {1-y}{y(1-y)}+frac y{y(1-y)}=frac 1y+frac 1{1-y}color{brown}{=frac 1y-frac 1{y-1}}$$
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add a comment |
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We write $$ frac {1}{y(1-y)}=frac {A}{y}+frac {B}{1-y}$$
Upon taking common denominator , we get $$frac {A(1-y)+By}{Y(1-y)}=frac {1}{y(1-y)}$$
Therefore we want to have,$$ A(1-y)+B(y)=1$$
Let $y=1$ and we get $B=1$ and let $y=0$ to get $A=1$
Thus $$ frac {1}{y(1-y)}=frac {1}{y}+frac {1}{1-y}=frac {1}{y}-frac {1} {y-1} $$
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Can you explain the part "Let y=1 and we get B=1 and let y=0 to get A=1"
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– Startec
Dec 27 '18 at 7:48
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We like to have the identity for every value of $y$, $ A(1−y)+B(y)=1$. If you plug $y=1$ in the identity you get $A(1-1)+B(1)=1$ which is the same as $B=1$. Similarly with $y=0$
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– Mohammad Riazi-Kermani
Dec 27 '18 at 9:50
add a comment |
Your Answer
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Here's a quick and easy way for simple or basic fractions$$frac 1{y(1-y)}=frac {color{blue}{1-y}+y}{y(color{blue}{1-y})}=frac {1-y}{y(1-y)}+frac y{y(1-y)}=frac 1y+frac 1{1-y}color{brown}{=frac 1y-frac 1{y-1}}$$
$endgroup$
add a comment |
$begingroup$
Here's a quick and easy way for simple or basic fractions$$frac 1{y(1-y)}=frac {color{blue}{1-y}+y}{y(color{blue}{1-y})}=frac {1-y}{y(1-y)}+frac y{y(1-y)}=frac 1y+frac 1{1-y}color{brown}{=frac 1y-frac 1{y-1}}$$
$endgroup$
add a comment |
$begingroup$
Here's a quick and easy way for simple or basic fractions$$frac 1{y(1-y)}=frac {color{blue}{1-y}+y}{y(color{blue}{1-y})}=frac {1-y}{y(1-y)}+frac y{y(1-y)}=frac 1y+frac 1{1-y}color{brown}{=frac 1y-frac 1{y-1}}$$
$endgroup$
Here's a quick and easy way for simple or basic fractions$$frac 1{y(1-y)}=frac {color{blue}{1-y}+y}{y(color{blue}{1-y})}=frac {1-y}{y(1-y)}+frac y{y(1-y)}=frac 1y+frac 1{1-y}color{brown}{=frac 1y-frac 1{y-1}}$$
answered Dec 27 '18 at 4:15
Frank W.Frank W.
3,7031321
3,7031321
add a comment |
add a comment |
$begingroup$
We write $$ frac {1}{y(1-y)}=frac {A}{y}+frac {B}{1-y}$$
Upon taking common denominator , we get $$frac {A(1-y)+By}{Y(1-y)}=frac {1}{y(1-y)}$$
Therefore we want to have,$$ A(1-y)+B(y)=1$$
Let $y=1$ and we get $B=1$ and let $y=0$ to get $A=1$
Thus $$ frac {1}{y(1-y)}=frac {1}{y}+frac {1}{1-y}=frac {1}{y}-frac {1} {y-1} $$
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$begingroup$
Can you explain the part "Let y=1 and we get B=1 and let y=0 to get A=1"
$endgroup$
– Startec
Dec 27 '18 at 7:48
$begingroup$
We like to have the identity for every value of $y$, $ A(1−y)+B(y)=1$. If you plug $y=1$ in the identity you get $A(1-1)+B(1)=1$ which is the same as $B=1$. Similarly with $y=0$
$endgroup$
– Mohammad Riazi-Kermani
Dec 27 '18 at 9:50
add a comment |
$begingroup$
We write $$ frac {1}{y(1-y)}=frac {A}{y}+frac {B}{1-y}$$
Upon taking common denominator , we get $$frac {A(1-y)+By}{Y(1-y)}=frac {1}{y(1-y)}$$
Therefore we want to have,$$ A(1-y)+B(y)=1$$
Let $y=1$ and we get $B=1$ and let $y=0$ to get $A=1$
Thus $$ frac {1}{y(1-y)}=frac {1}{y}+frac {1}{1-y}=frac {1}{y}-frac {1} {y-1} $$
$endgroup$
$begingroup$
Can you explain the part "Let y=1 and we get B=1 and let y=0 to get A=1"
$endgroup$
– Startec
Dec 27 '18 at 7:48
$begingroup$
We like to have the identity for every value of $y$, $ A(1−y)+B(y)=1$. If you plug $y=1$ in the identity you get $A(1-1)+B(1)=1$ which is the same as $B=1$. Similarly with $y=0$
$endgroup$
– Mohammad Riazi-Kermani
Dec 27 '18 at 9:50
add a comment |
$begingroup$
We write $$ frac {1}{y(1-y)}=frac {A}{y}+frac {B}{1-y}$$
Upon taking common denominator , we get $$frac {A(1-y)+By}{Y(1-y)}=frac {1}{y(1-y)}$$
Therefore we want to have,$$ A(1-y)+B(y)=1$$
Let $y=1$ and we get $B=1$ and let $y=0$ to get $A=1$
Thus $$ frac {1}{y(1-y)}=frac {1}{y}+frac {1}{1-y}=frac {1}{y}-frac {1} {y-1} $$
$endgroup$
We write $$ frac {1}{y(1-y)}=frac {A}{y}+frac {B}{1-y}$$
Upon taking common denominator , we get $$frac {A(1-y)+By}{Y(1-y)}=frac {1}{y(1-y)}$$
Therefore we want to have,$$ A(1-y)+B(y)=1$$
Let $y=1$ and we get $B=1$ and let $y=0$ to get $A=1$
Thus $$ frac {1}{y(1-y)}=frac {1}{y}+frac {1}{1-y}=frac {1}{y}-frac {1} {y-1} $$
answered Dec 27 '18 at 4:27
Mohammad Riazi-KermaniMohammad Riazi-Kermani
41.6k42061
41.6k42061
$begingroup$
Can you explain the part "Let y=1 and we get B=1 and let y=0 to get A=1"
$endgroup$
– Startec
Dec 27 '18 at 7:48
$begingroup$
We like to have the identity for every value of $y$, $ A(1−y)+B(y)=1$. If you plug $y=1$ in the identity you get $A(1-1)+B(1)=1$ which is the same as $B=1$. Similarly with $y=0$
$endgroup$
– Mohammad Riazi-Kermani
Dec 27 '18 at 9:50
add a comment |
$begingroup$
Can you explain the part "Let y=1 and we get B=1 and let y=0 to get A=1"
$endgroup$
– Startec
Dec 27 '18 at 7:48
$begingroup$
We like to have the identity for every value of $y$, $ A(1−y)+B(y)=1$. If you plug $y=1$ in the identity you get $A(1-1)+B(1)=1$ which is the same as $B=1$. Similarly with $y=0$
$endgroup$
– Mohammad Riazi-Kermani
Dec 27 '18 at 9:50
$begingroup$
Can you explain the part "Let y=1 and we get B=1 and let y=0 to get A=1"
$endgroup$
– Startec
Dec 27 '18 at 7:48
$begingroup$
Can you explain the part "Let y=1 and we get B=1 and let y=0 to get A=1"
$endgroup$
– Startec
Dec 27 '18 at 7:48
$begingroup$
We like to have the identity for every value of $y$, $ A(1−y)+B(y)=1$. If you plug $y=1$ in the identity you get $A(1-1)+B(1)=1$ which is the same as $B=1$. Similarly with $y=0$
$endgroup$
– Mohammad Riazi-Kermani
Dec 27 '18 at 9:50
$begingroup$
We like to have the identity for every value of $y$, $ A(1−y)+B(y)=1$. If you plug $y=1$ in the identity you get $A(1-1)+B(1)=1$ which is the same as $B=1$. Similarly with $y=0$
$endgroup$
– Mohammad Riazi-Kermani
Dec 27 '18 at 9:50
add a comment |
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1
$begingroup$
Numerator $1=y+1-y$
$endgroup$
– lab bhattacharjee
Dec 27 '18 at 4:13
1
$begingroup$
This can be done with partial fraction decomposition. en.wikipedia.org/wiki/Partial_fraction_decomposition
$endgroup$
– CyclotomicField
Dec 27 '18 at 4:14