Whenever $y'$ is in $sin(y')$ or as a power, the degree of the polynomial equation is not defined, why?
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In my textbook it is written that for $y'+ sinleft(y'right)= 0$ the degree is not defined.
Is it by definition or there is some reasoning behind this?
calculus ordinary-differential-equations
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add a comment |
$begingroup$
In my textbook it is written that for $y'+ sinleft(y'right)= 0$ the degree is not defined.
Is it by definition or there is some reasoning behind this?
calculus ordinary-differential-equations
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2
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What do you think the degree ought to be? What's the degree of $$2y'-frac16(y')^3+frac1{120}(y')^5-frac1{5040}(y')^7+cdots?$$
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– bof
Sep 24 '17 at 7:47
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Ohhhhhhhhh so its not possible to assign a value, then its undefined thanks sooo much
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– WhiteHole
Sep 24 '17 at 8:05
add a comment |
$begingroup$
In my textbook it is written that for $y'+ sinleft(y'right)= 0$ the degree is not defined.
Is it by definition or there is some reasoning behind this?
calculus ordinary-differential-equations
$endgroup$
In my textbook it is written that for $y'+ sinleft(y'right)= 0$ the degree is not defined.
Is it by definition or there is some reasoning behind this?
calculus ordinary-differential-equations
calculus ordinary-differential-equations
edited Nov 29 '18 at 14:46
Davide Giraudo
126k16150261
126k16150261
asked Sep 24 '17 at 5:13
WhiteHoleWhiteHole
216
216
2
$begingroup$
What do you think the degree ought to be? What's the degree of $$2y'-frac16(y')^3+frac1{120}(y')^5-frac1{5040}(y')^7+cdots?$$
$endgroup$
– bof
Sep 24 '17 at 7:47
$begingroup$
Ohhhhhhhhh so its not possible to assign a value, then its undefined thanks sooo much
$endgroup$
– WhiteHole
Sep 24 '17 at 8:05
add a comment |
2
$begingroup$
What do you think the degree ought to be? What's the degree of $$2y'-frac16(y')^3+frac1{120}(y')^5-frac1{5040}(y')^7+cdots?$$
$endgroup$
– bof
Sep 24 '17 at 7:47
$begingroup$
Ohhhhhhhhh so its not possible to assign a value, then its undefined thanks sooo much
$endgroup$
– WhiteHole
Sep 24 '17 at 8:05
2
2
$begingroup$
What do you think the degree ought to be? What's the degree of $$2y'-frac16(y')^3+frac1{120}(y')^5-frac1{5040}(y')^7+cdots?$$
$endgroup$
– bof
Sep 24 '17 at 7:47
$begingroup$
What do you think the degree ought to be? What's the degree of $$2y'-frac16(y')^3+frac1{120}(y')^5-frac1{5040}(y')^7+cdots?$$
$endgroup$
– bof
Sep 24 '17 at 7:47
$begingroup$
Ohhhhhhhhh so its not possible to assign a value, then its undefined thanks sooo much
$endgroup$
– WhiteHole
Sep 24 '17 at 8:05
$begingroup$
Ohhhhhhhhh so its not possible to assign a value, then its undefined thanks sooo much
$endgroup$
– WhiteHole
Sep 24 '17 at 8:05
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
begin{array}{l}
y' + sin left( {y'} right) = 0\
{rm{Since, by Maclaurin series expansion of \}}sin left( x right){rm {is}}\
sin left( x right) = x - frac{{{x^3}}}{{3!}} + frac{{{x^5}}}{{5!}} - frac{{{x^7}}}{{7!}} + cdots \
{rm{Then,the first order differential equation can be written as }}\
y' + sin left( {y'} right) = 0\
y' + y' - frac{{{{left( {y'} right)}^3}}}{{3!}} + frac{{{{left( {y'} right)}^5}}}{{5!}} - frac{{{{left( {y'} right)}^7}}}{{7!}} + cdots = 0
end{array}
Then from the above equation, it is clear that there are infinite terms in the equation, so the degree of the equation can not be defined.
$endgroup$
add a comment |
Your Answer
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1 Answer
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$begingroup$
begin{array}{l}
y' + sin left( {y'} right) = 0\
{rm{Since, by Maclaurin series expansion of \}}sin left( x right){rm {is}}\
sin left( x right) = x - frac{{{x^3}}}{{3!}} + frac{{{x^5}}}{{5!}} - frac{{{x^7}}}{{7!}} + cdots \
{rm{Then,the first order differential equation can be written as }}\
y' + sin left( {y'} right) = 0\
y' + y' - frac{{{{left( {y'} right)}^3}}}{{3!}} + frac{{{{left( {y'} right)}^5}}}{{5!}} - frac{{{{left( {y'} right)}^7}}}{{7!}} + cdots = 0
end{array}
Then from the above equation, it is clear that there are infinite terms in the equation, so the degree of the equation can not be defined.
$endgroup$
add a comment |
$begingroup$
begin{array}{l}
y' + sin left( {y'} right) = 0\
{rm{Since, by Maclaurin series expansion of \}}sin left( x right){rm {is}}\
sin left( x right) = x - frac{{{x^3}}}{{3!}} + frac{{{x^5}}}{{5!}} - frac{{{x^7}}}{{7!}} + cdots \
{rm{Then,the first order differential equation can be written as }}\
y' + sin left( {y'} right) = 0\
y' + y' - frac{{{{left( {y'} right)}^3}}}{{3!}} + frac{{{{left( {y'} right)}^5}}}{{5!}} - frac{{{{left( {y'} right)}^7}}}{{7!}} + cdots = 0
end{array}
Then from the above equation, it is clear that there are infinite terms in the equation, so the degree of the equation can not be defined.
$endgroup$
add a comment |
$begingroup$
begin{array}{l}
y' + sin left( {y'} right) = 0\
{rm{Since, by Maclaurin series expansion of \}}sin left( x right){rm {is}}\
sin left( x right) = x - frac{{{x^3}}}{{3!}} + frac{{{x^5}}}{{5!}} - frac{{{x^7}}}{{7!}} + cdots \
{rm{Then,the first order differential equation can be written as }}\
y' + sin left( {y'} right) = 0\
y' + y' - frac{{{{left( {y'} right)}^3}}}{{3!}} + frac{{{{left( {y'} right)}^5}}}{{5!}} - frac{{{{left( {y'} right)}^7}}}{{7!}} + cdots = 0
end{array}
Then from the above equation, it is clear that there are infinite terms in the equation, so the degree of the equation can not be defined.
$endgroup$
begin{array}{l}
y' + sin left( {y'} right) = 0\
{rm{Since, by Maclaurin series expansion of \}}sin left( x right){rm {is}}\
sin left( x right) = x - frac{{{x^3}}}{{3!}} + frac{{{x^5}}}{{5!}} - frac{{{x^7}}}{{7!}} + cdots \
{rm{Then,the first order differential equation can be written as }}\
y' + sin left( {y'} right) = 0\
y' + y' - frac{{{{left( {y'} right)}^3}}}{{3!}} + frac{{{{left( {y'} right)}^5}}}{{5!}} - frac{{{{left( {y'} right)}^7}}}{{7!}} + cdots = 0
end{array}
Then from the above equation, it is clear that there are infinite terms in the equation, so the degree of the equation can not be defined.
answered Nov 29 '18 at 17:08
Krishna SrivastavKrishna Srivastav
894
894
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$begingroup$
What do you think the degree ought to be? What's the degree of $$2y'-frac16(y')^3+frac1{120}(y')^5-frac1{5040}(y')^7+cdots?$$
$endgroup$
– bof
Sep 24 '17 at 7:47
$begingroup$
Ohhhhhhhhh so its not possible to assign a value, then its undefined thanks sooo much
$endgroup$
– WhiteHole
Sep 24 '17 at 8:05