How do I find the solutions of $|x-2|^{10x^2-1}=|x-2|^{3x}$?
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How do I find the solutions of the following equation: $$|x-2|^{10x^2-1}=|x-2|^{3x} ?$$
I found that this equation has 5 solutions, 4 positive and 1 negative by looking the graph:
Question: How do I compute the values of these roots manually?
algebra-precalculus logarithms
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add a comment |
$begingroup$
How do I find the solutions of the following equation: $$|x-2|^{10x^2-1}=|x-2|^{3x} ?$$
I found that this equation has 5 solutions, 4 positive and 1 negative by looking the graph:
Question: How do I compute the values of these roots manually?
algebra-precalculus logarithms
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$begingroup$
math.stackexchange.com/questions/3157637/…
$endgroup$
– lab bhattacharjee
Mar 27 at 19:27
add a comment |
$begingroup$
How do I find the solutions of the following equation: $$|x-2|^{10x^2-1}=|x-2|^{3x} ?$$
I found that this equation has 5 solutions, 4 positive and 1 negative by looking the graph:
Question: How do I compute the values of these roots manually?
algebra-precalculus logarithms
$endgroup$
How do I find the solutions of the following equation: $$|x-2|^{10x^2-1}=|x-2|^{3x} ?$$
I found that this equation has 5 solutions, 4 positive and 1 negative by looking the graph:
Question: How do I compute the values of these roots manually?
algebra-precalculus logarithms
algebra-precalculus logarithms
edited 14 hours ago
Jack
27.7k1782204
27.7k1782204
asked Mar 27 at 18:36
Namami ShankerNamami Shanker
171
171
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math.stackexchange.com/questions/3157637/…
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– lab bhattacharjee
Mar 27 at 19:27
add a comment |
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math.stackexchange.com/questions/3157637/…
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– lab bhattacharjee
Mar 27 at 19:27
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math.stackexchange.com/questions/3157637/…
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– lab bhattacharjee
Mar 27 at 19:27
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– lab bhattacharjee
Mar 27 at 19:27
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4 Answers
4
active
oldest
votes
$begingroup$
We see that $x=2$ is one solution. Let $xne 2$.
Taking $log$ we get $$(10x^2-1)log|x-2|=3xlog|x-2|$$
So one solution is $log |x-2| = 0implies |x-2| =1 implies x-2=pm1 $, so $x=3$ or $x=1$.
Say $log |x-2| ne 0$ then $10x^2-1 = 3x$ so $x= {1over 2}$ and $x=-{1over 5}$.
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add a comment |
$begingroup$
So rearranging gives
$$|x-2|^{10x^2-1}-|x-2|^{3x}=0$$
$$|x-2|^{3x}(|x-2|^{10x^2-3x-1}-1)=0$$
So either $x=2$ to achieve zero in the first factor, $|x-2|=1implies x=1,3$ in order for the second factor to be $1-1=0$. We can also have $10x^2-3x-1=0implies x=-frac15 , frac12$ where the power in the second factor is $0$ and hence also causes $1-1=0$.
$endgroup$
add a comment |
$begingroup$
Hint
Either $$x=2$$or$$|x-2|^{10x^2-3x-1}=1$$what are all the answers of $a^b=1$? (In our case, $x=3$ is one answer. What about the others?)
$endgroup$
add a comment |
$begingroup$
We get easy that $x=2$ is one solution. Now let $xneq 2$, then it must be $10x^2-1=3x$. Can you finish? Hint: $x=3$ and $x=1$ are also solutions.
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Yes thank you sir.
$endgroup$
– Namami Shanker
Mar 27 at 18:45
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This does not give all of the solutions.
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– Peter Foreman
Mar 27 at 18:47
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The point about $x=3$ and $x=1$ is that these make $|x-2|=1$, and then $|x-2|^p = 1$ for any $p$. If $x ne 1, 2, 3$, then we must have $10 x^2-1 = 3x$, because $a^t$ is a one-to-one function of $t$ if $0 < a < 1$ or $a > 1$.
$endgroup$
– Robert Israel
Mar 27 at 18:54
add a comment |
Your Answer
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4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
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votes
active
oldest
votes
$begingroup$
We see that $x=2$ is one solution. Let $xne 2$.
Taking $log$ we get $$(10x^2-1)log|x-2|=3xlog|x-2|$$
So one solution is $log |x-2| = 0implies |x-2| =1 implies x-2=pm1 $, so $x=3$ or $x=1$.
Say $log |x-2| ne 0$ then $10x^2-1 = 3x$ so $x= {1over 2}$ and $x=-{1over 5}$.
$endgroup$
add a comment |
$begingroup$
We see that $x=2$ is one solution. Let $xne 2$.
Taking $log$ we get $$(10x^2-1)log|x-2|=3xlog|x-2|$$
So one solution is $log |x-2| = 0implies |x-2| =1 implies x-2=pm1 $, so $x=3$ or $x=1$.
Say $log |x-2| ne 0$ then $10x^2-1 = 3x$ so $x= {1over 2}$ and $x=-{1over 5}$.
$endgroup$
add a comment |
$begingroup$
We see that $x=2$ is one solution. Let $xne 2$.
Taking $log$ we get $$(10x^2-1)log|x-2|=3xlog|x-2|$$
So one solution is $log |x-2| = 0implies |x-2| =1 implies x-2=pm1 $, so $x=3$ or $x=1$.
Say $log |x-2| ne 0$ then $10x^2-1 = 3x$ so $x= {1over 2}$ and $x=-{1over 5}$.
$endgroup$
We see that $x=2$ is one solution. Let $xne 2$.
Taking $log$ we get $$(10x^2-1)log|x-2|=3xlog|x-2|$$
So one solution is $log |x-2| = 0implies |x-2| =1 implies x-2=pm1 $, so $x=3$ or $x=1$.
Say $log |x-2| ne 0$ then $10x^2-1 = 3x$ so $x= {1over 2}$ and $x=-{1over 5}$.
edited Mar 27 at 20:39
Moo
5,64031020
5,64031020
answered Mar 27 at 18:43
Maria MazurMaria Mazur
49.9k1361124
49.9k1361124
add a comment |
add a comment |
$begingroup$
So rearranging gives
$$|x-2|^{10x^2-1}-|x-2|^{3x}=0$$
$$|x-2|^{3x}(|x-2|^{10x^2-3x-1}-1)=0$$
So either $x=2$ to achieve zero in the first factor, $|x-2|=1implies x=1,3$ in order for the second factor to be $1-1=0$. We can also have $10x^2-3x-1=0implies x=-frac15 , frac12$ where the power in the second factor is $0$ and hence also causes $1-1=0$.
$endgroup$
add a comment |
$begingroup$
So rearranging gives
$$|x-2|^{10x^2-1}-|x-2|^{3x}=0$$
$$|x-2|^{3x}(|x-2|^{10x^2-3x-1}-1)=0$$
So either $x=2$ to achieve zero in the first factor, $|x-2|=1implies x=1,3$ in order for the second factor to be $1-1=0$. We can also have $10x^2-3x-1=0implies x=-frac15 , frac12$ where the power in the second factor is $0$ and hence also causes $1-1=0$.
$endgroup$
add a comment |
$begingroup$
So rearranging gives
$$|x-2|^{10x^2-1}-|x-2|^{3x}=0$$
$$|x-2|^{3x}(|x-2|^{10x^2-3x-1}-1)=0$$
So either $x=2$ to achieve zero in the first factor, $|x-2|=1implies x=1,3$ in order for the second factor to be $1-1=0$. We can also have $10x^2-3x-1=0implies x=-frac15 , frac12$ where the power in the second factor is $0$ and hence also causes $1-1=0$.
$endgroup$
So rearranging gives
$$|x-2|^{10x^2-1}-|x-2|^{3x}=0$$
$$|x-2|^{3x}(|x-2|^{10x^2-3x-1}-1)=0$$
So either $x=2$ to achieve zero in the first factor, $|x-2|=1implies x=1,3$ in order for the second factor to be $1-1=0$. We can also have $10x^2-3x-1=0implies x=-frac15 , frac12$ where the power in the second factor is $0$ and hence also causes $1-1=0$.
answered Mar 27 at 18:45
Peter ForemanPeter Foreman
5,9091317
5,9091317
add a comment |
add a comment |
$begingroup$
Hint
Either $$x=2$$or$$|x-2|^{10x^2-3x-1}=1$$what are all the answers of $a^b=1$? (In our case, $x=3$ is one answer. What about the others?)
$endgroup$
add a comment |
$begingroup$
Hint
Either $$x=2$$or$$|x-2|^{10x^2-3x-1}=1$$what are all the answers of $a^b=1$? (In our case, $x=3$ is one answer. What about the others?)
$endgroup$
add a comment |
$begingroup$
Hint
Either $$x=2$$or$$|x-2|^{10x^2-3x-1}=1$$what are all the answers of $a^b=1$? (In our case, $x=3$ is one answer. What about the others?)
$endgroup$
Hint
Either $$x=2$$or$$|x-2|^{10x^2-3x-1}=1$$what are all the answers of $a^b=1$? (In our case, $x=3$ is one answer. What about the others?)
answered Mar 27 at 19:07
Mostafa AyazMostafa Ayaz
18.2k31040
18.2k31040
add a comment |
add a comment |
$begingroup$
We get easy that $x=2$ is one solution. Now let $xneq 2$, then it must be $10x^2-1=3x$. Can you finish? Hint: $x=3$ and $x=1$ are also solutions.
$endgroup$
$begingroup$
Yes thank you sir.
$endgroup$
– Namami Shanker
Mar 27 at 18:45
$begingroup$
This does not give all of the solutions.
$endgroup$
– Peter Foreman
Mar 27 at 18:47
$begingroup$
The point about $x=3$ and $x=1$ is that these make $|x-2|=1$, and then $|x-2|^p = 1$ for any $p$. If $x ne 1, 2, 3$, then we must have $10 x^2-1 = 3x$, because $a^t$ is a one-to-one function of $t$ if $0 < a < 1$ or $a > 1$.
$endgroup$
– Robert Israel
Mar 27 at 18:54
add a comment |
$begingroup$
We get easy that $x=2$ is one solution. Now let $xneq 2$, then it must be $10x^2-1=3x$. Can you finish? Hint: $x=3$ and $x=1$ are also solutions.
$endgroup$
$begingroup$
Yes thank you sir.
$endgroup$
– Namami Shanker
Mar 27 at 18:45
$begingroup$
This does not give all of the solutions.
$endgroup$
– Peter Foreman
Mar 27 at 18:47
$begingroup$
The point about $x=3$ and $x=1$ is that these make $|x-2|=1$, and then $|x-2|^p = 1$ for any $p$. If $x ne 1, 2, 3$, then we must have $10 x^2-1 = 3x$, because $a^t$ is a one-to-one function of $t$ if $0 < a < 1$ or $a > 1$.
$endgroup$
– Robert Israel
Mar 27 at 18:54
add a comment |
$begingroup$
We get easy that $x=2$ is one solution. Now let $xneq 2$, then it must be $10x^2-1=3x$. Can you finish? Hint: $x=3$ and $x=1$ are also solutions.
$endgroup$
We get easy that $x=2$ is one solution. Now let $xneq 2$, then it must be $10x^2-1=3x$. Can you finish? Hint: $x=3$ and $x=1$ are also solutions.
edited Mar 28 at 2:08
Solomon Ucko
14719
14719
answered Mar 27 at 18:41
Dr. Sonnhard GraubnerDr. Sonnhard Graubner
78.6k42867
78.6k42867
$begingroup$
Yes thank you sir.
$endgroup$
– Namami Shanker
Mar 27 at 18:45
$begingroup$
This does not give all of the solutions.
$endgroup$
– Peter Foreman
Mar 27 at 18:47
$begingroup$
The point about $x=3$ and $x=1$ is that these make $|x-2|=1$, and then $|x-2|^p = 1$ for any $p$. If $x ne 1, 2, 3$, then we must have $10 x^2-1 = 3x$, because $a^t$ is a one-to-one function of $t$ if $0 < a < 1$ or $a > 1$.
$endgroup$
– Robert Israel
Mar 27 at 18:54
add a comment |
$begingroup$
Yes thank you sir.
$endgroup$
– Namami Shanker
Mar 27 at 18:45
$begingroup$
This does not give all of the solutions.
$endgroup$
– Peter Foreman
Mar 27 at 18:47
$begingroup$
The point about $x=3$ and $x=1$ is that these make $|x-2|=1$, and then $|x-2|^p = 1$ for any $p$. If $x ne 1, 2, 3$, then we must have $10 x^2-1 = 3x$, because $a^t$ is a one-to-one function of $t$ if $0 < a < 1$ or $a > 1$.
$endgroup$
– Robert Israel
Mar 27 at 18:54
$begingroup$
Yes thank you sir.
$endgroup$
– Namami Shanker
Mar 27 at 18:45
$begingroup$
Yes thank you sir.
$endgroup$
– Namami Shanker
Mar 27 at 18:45
$begingroup$
This does not give all of the solutions.
$endgroup$
– Peter Foreman
Mar 27 at 18:47
$begingroup$
This does not give all of the solutions.
$endgroup$
– Peter Foreman
Mar 27 at 18:47
$begingroup$
The point about $x=3$ and $x=1$ is that these make $|x-2|=1$, and then $|x-2|^p = 1$ for any $p$. If $x ne 1, 2, 3$, then we must have $10 x^2-1 = 3x$, because $a^t$ is a one-to-one function of $t$ if $0 < a < 1$ or $a > 1$.
$endgroup$
– Robert Israel
Mar 27 at 18:54
$begingroup$
The point about $x=3$ and $x=1$ is that these make $|x-2|=1$, and then $|x-2|^p = 1$ for any $p$. If $x ne 1, 2, 3$, then we must have $10 x^2-1 = 3x$, because $a^t$ is a one-to-one function of $t$ if $0 < a < 1$ or $a > 1$.
$endgroup$
– Robert Israel
Mar 27 at 18:54
add a comment |
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$begingroup$
math.stackexchange.com/questions/3157637/…
$endgroup$
– lab bhattacharjee
Mar 27 at 19:27