How do I simplify $fraclog_7 32log_7 8cdotsqrt2$?
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So far I have got $log_7 2^5 - log_7 2^3 + log_7 2^1/2$ and am unable to proceed. Am I, on the right track so far? and how do I proceed? thank you!
logarithms
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up vote
1
down vote
favorite
So far I have got $log_7 2^5 - log_7 2^3 + log_7 2^1/2$ and am unable to proceed. Am I, on the right track so far? and how do I proceed? thank you!
logarithms
BTW guys the x is times not 8x sorry!!
â Negrawh
Sep 7 at 9:39
It is $log_2^3 2^5 cdot sqrt 2$
â Mohammad Zuhair Khan
Sep 7 at 9:47
Is it $fraclog_732 log_78cdot sqrt2$ ?
â tarit goswami
Sep 7 at 9:47
Welcome to MathSE. Please read this MathJax tutorial, which explains how to typeset mathematics on this site. It is not clear whether you meant $fraclog_7 32log_7 8 cdot sqrt2$ or $fraclog_7 32log_7 8sqrt2$.
â N. F. Taussig
Sep 7 at 9:55
@N.F.Taussig I want the second one
â Negrawh
Sep 7 at 11:14
add a comment |Â
up vote
1
down vote
favorite
up vote
1
down vote
favorite
So far I have got $log_7 2^5 - log_7 2^3 + log_7 2^1/2$ and am unable to proceed. Am I, on the right track so far? and how do I proceed? thank you!
logarithms
So far I have got $log_7 2^5 - log_7 2^3 + log_7 2^1/2$ and am unable to proceed. Am I, on the right track so far? and how do I proceed? thank you!
logarithms
logarithms
edited Sep 7 at 11:27
N. F. Taussig
39.7k93153
39.7k93153
asked Sep 7 at 9:39
Negrawh
84
84
BTW guys the x is times not 8x sorry!!
â Negrawh
Sep 7 at 9:39
It is $log_2^3 2^5 cdot sqrt 2$
â Mohammad Zuhair Khan
Sep 7 at 9:47
Is it $fraclog_732 log_78cdot sqrt2$ ?
â tarit goswami
Sep 7 at 9:47
Welcome to MathSE. Please read this MathJax tutorial, which explains how to typeset mathematics on this site. It is not clear whether you meant $fraclog_7 32log_7 8 cdot sqrt2$ or $fraclog_7 32log_7 8sqrt2$.
â N. F. Taussig
Sep 7 at 9:55
@N.F.Taussig I want the second one
â Negrawh
Sep 7 at 11:14
add a comment |Â
BTW guys the x is times not 8x sorry!!
â Negrawh
Sep 7 at 9:39
It is $log_2^3 2^5 cdot sqrt 2$
â Mohammad Zuhair Khan
Sep 7 at 9:47
Is it $fraclog_732 log_78cdot sqrt2$ ?
â tarit goswami
Sep 7 at 9:47
Welcome to MathSE. Please read this MathJax tutorial, which explains how to typeset mathematics on this site. It is not clear whether you meant $fraclog_7 32log_7 8 cdot sqrt2$ or $fraclog_7 32log_7 8sqrt2$.
â N. F. Taussig
Sep 7 at 9:55
@N.F.Taussig I want the second one
â Negrawh
Sep 7 at 11:14
BTW guys the x is times not 8x sorry!!
â Negrawh
Sep 7 at 9:39
BTW guys the x is times not 8x sorry!!
â Negrawh
Sep 7 at 9:39
It is $log_2^3 2^5 cdot sqrt 2$
â Mohammad Zuhair Khan
Sep 7 at 9:47
It is $log_2^3 2^5 cdot sqrt 2$
â Mohammad Zuhair Khan
Sep 7 at 9:47
Is it $fraclog_732 log_78cdot sqrt2$ ?
â tarit goswami
Sep 7 at 9:47
Is it $fraclog_732 log_78cdot sqrt2$ ?
â tarit goswami
Sep 7 at 9:47
Welcome to MathSE. Please read this MathJax tutorial, which explains how to typeset mathematics on this site. It is not clear whether you meant $fraclog_7 32log_7 8 cdot sqrt2$ or $fraclog_7 32log_7 8sqrt2$.
â N. F. Taussig
Sep 7 at 9:55
Welcome to MathSE. Please read this MathJax tutorial, which explains how to typeset mathematics on this site. It is not clear whether you meant $fraclog_7 32log_7 8 cdot sqrt2$ or $fraclog_7 32log_7 8sqrt2$.
â N. F. Taussig
Sep 7 at 9:55
@N.F.Taussig I want the second one
â Negrawh
Sep 7 at 11:14
@N.F.Taussig I want the second one
â Negrawh
Sep 7 at 11:14
add a comment |Â
2 Answers
2
active
oldest
votes
up vote
3
down vote
accepted
Your expansion is not correct. If $b, x, y > 0$, with $b neq 1$, then
beginalign*
log_b (xy) & = log_b x + log_b y\
log_b left(fracxyright) & = log_b x - log_b y
endalign*
However, you have
$$fraclog_7 32log_7 8sqrt2$$
which is a quotient of logarithms, not the logarithm of a quotient, so you cannot apply those rules here.
However, your observations that $32 = 2^5$, $8 = 2^3$, and $sqrt2 = 2^1/2$ would be useful if we were working with logarithms to the base $2$. To do so, we use the Change of Base Formula. Let $a, b, x > 0$, with $a, b neq 1$. Then
$$log_a x = fraclog_b xlog_b a$$
By setting $a = 7$ and $b = 2$, we obtain
beginalign*
fraclog_7 32log_7 8sqrt2 & = fracdfraclog_2 32log_2 7dfraclog_2 8sqrt2log_2 7\
& = fraclog_2 32log_2 8sqrt2\
& = fraclog_2 2^5log_2 2^32^1/2\
& = frac5log_2 2^7/2\
& = frac5frac72\
& = frac107
endalign*
Thanks for pointing out my mistake and very helpful!
â Negrawh
Sep 8 at 11:30
add a comment |Â
up vote
2
down vote
You can use the formula
$$fraclog_ablog_ac=log_cb$$
$$fraclog_732log_78cdot sqrt2=left(log_832right)cdot sqrt2=frac5sqrt23$$
Or If you are looking for this
$$fraclog_732log_78sqrt2 =left(log_8sqrt232right)=frac5frac72=frac107$$
Thank you !!!!!
â Negrawh
Sep 8 at 11:30
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
accepted
Your expansion is not correct. If $b, x, y > 0$, with $b neq 1$, then
beginalign*
log_b (xy) & = log_b x + log_b y\
log_b left(fracxyright) & = log_b x - log_b y
endalign*
However, you have
$$fraclog_7 32log_7 8sqrt2$$
which is a quotient of logarithms, not the logarithm of a quotient, so you cannot apply those rules here.
However, your observations that $32 = 2^5$, $8 = 2^3$, and $sqrt2 = 2^1/2$ would be useful if we were working with logarithms to the base $2$. To do so, we use the Change of Base Formula. Let $a, b, x > 0$, with $a, b neq 1$. Then
$$log_a x = fraclog_b xlog_b a$$
By setting $a = 7$ and $b = 2$, we obtain
beginalign*
fraclog_7 32log_7 8sqrt2 & = fracdfraclog_2 32log_2 7dfraclog_2 8sqrt2log_2 7\
& = fraclog_2 32log_2 8sqrt2\
& = fraclog_2 2^5log_2 2^32^1/2\
& = frac5log_2 2^7/2\
& = frac5frac72\
& = frac107
endalign*
Thanks for pointing out my mistake and very helpful!
â Negrawh
Sep 8 at 11:30
add a comment |Â
up vote
3
down vote
accepted
Your expansion is not correct. If $b, x, y > 0$, with $b neq 1$, then
beginalign*
log_b (xy) & = log_b x + log_b y\
log_b left(fracxyright) & = log_b x - log_b y
endalign*
However, you have
$$fraclog_7 32log_7 8sqrt2$$
which is a quotient of logarithms, not the logarithm of a quotient, so you cannot apply those rules here.
However, your observations that $32 = 2^5$, $8 = 2^3$, and $sqrt2 = 2^1/2$ would be useful if we were working with logarithms to the base $2$. To do so, we use the Change of Base Formula. Let $a, b, x > 0$, with $a, b neq 1$. Then
$$log_a x = fraclog_b xlog_b a$$
By setting $a = 7$ and $b = 2$, we obtain
beginalign*
fraclog_7 32log_7 8sqrt2 & = fracdfraclog_2 32log_2 7dfraclog_2 8sqrt2log_2 7\
& = fraclog_2 32log_2 8sqrt2\
& = fraclog_2 2^5log_2 2^32^1/2\
& = frac5log_2 2^7/2\
& = frac5frac72\
& = frac107
endalign*
Thanks for pointing out my mistake and very helpful!
â Negrawh
Sep 8 at 11:30
add a comment |Â
up vote
3
down vote
accepted
up vote
3
down vote
accepted
Your expansion is not correct. If $b, x, y > 0$, with $b neq 1$, then
beginalign*
log_b (xy) & = log_b x + log_b y\
log_b left(fracxyright) & = log_b x - log_b y
endalign*
However, you have
$$fraclog_7 32log_7 8sqrt2$$
which is a quotient of logarithms, not the logarithm of a quotient, so you cannot apply those rules here.
However, your observations that $32 = 2^5$, $8 = 2^3$, and $sqrt2 = 2^1/2$ would be useful if we were working with logarithms to the base $2$. To do so, we use the Change of Base Formula. Let $a, b, x > 0$, with $a, b neq 1$. Then
$$log_a x = fraclog_b xlog_b a$$
By setting $a = 7$ and $b = 2$, we obtain
beginalign*
fraclog_7 32log_7 8sqrt2 & = fracdfraclog_2 32log_2 7dfraclog_2 8sqrt2log_2 7\
& = fraclog_2 32log_2 8sqrt2\
& = fraclog_2 2^5log_2 2^32^1/2\
& = frac5log_2 2^7/2\
& = frac5frac72\
& = frac107
endalign*
Your expansion is not correct. If $b, x, y > 0$, with $b neq 1$, then
beginalign*
log_b (xy) & = log_b x + log_b y\
log_b left(fracxyright) & = log_b x - log_b y
endalign*
However, you have
$$fraclog_7 32log_7 8sqrt2$$
which is a quotient of logarithms, not the logarithm of a quotient, so you cannot apply those rules here.
However, your observations that $32 = 2^5$, $8 = 2^3$, and $sqrt2 = 2^1/2$ would be useful if we were working with logarithms to the base $2$. To do so, we use the Change of Base Formula. Let $a, b, x > 0$, with $a, b neq 1$. Then
$$log_a x = fraclog_b xlog_b a$$
By setting $a = 7$ and $b = 2$, we obtain
beginalign*
fraclog_7 32log_7 8sqrt2 & = fracdfraclog_2 32log_2 7dfraclog_2 8sqrt2log_2 7\
& = fraclog_2 32log_2 8sqrt2\
& = fraclog_2 2^5log_2 2^32^1/2\
& = frac5log_2 2^7/2\
& = frac5frac72\
& = frac107
endalign*
answered Sep 7 at 13:53
N. F. Taussig
39.7k93153
39.7k93153
Thanks for pointing out my mistake and very helpful!
â Negrawh
Sep 8 at 11:30
add a comment |Â
Thanks for pointing out my mistake and very helpful!
â Negrawh
Sep 8 at 11:30
Thanks for pointing out my mistake and very helpful!
â Negrawh
Sep 8 at 11:30
Thanks for pointing out my mistake and very helpful!
â Negrawh
Sep 8 at 11:30
add a comment |Â
up vote
2
down vote
You can use the formula
$$fraclog_ablog_ac=log_cb$$
$$fraclog_732log_78cdot sqrt2=left(log_832right)cdot sqrt2=frac5sqrt23$$
Or If you are looking for this
$$fraclog_732log_78sqrt2 =left(log_8sqrt232right)=frac5frac72=frac107$$
Thank you !!!!!
â Negrawh
Sep 8 at 11:30
add a comment |Â
up vote
2
down vote
You can use the formula
$$fraclog_ablog_ac=log_cb$$
$$fraclog_732log_78cdot sqrt2=left(log_832right)cdot sqrt2=frac5sqrt23$$
Or If you are looking for this
$$fraclog_732log_78sqrt2 =left(log_8sqrt232right)=frac5frac72=frac107$$
Thank you !!!!!
â Negrawh
Sep 8 at 11:30
add a comment |Â
up vote
2
down vote
up vote
2
down vote
You can use the formula
$$fraclog_ablog_ac=log_cb$$
$$fraclog_732log_78cdot sqrt2=left(log_832right)cdot sqrt2=frac5sqrt23$$
Or If you are looking for this
$$fraclog_732log_78sqrt2 =left(log_8sqrt232right)=frac5frac72=frac107$$
You can use the formula
$$fraclog_ablog_ac=log_cb$$
$$fraclog_732log_78cdot sqrt2=left(log_832right)cdot sqrt2=frac5sqrt23$$
Or If you are looking for this
$$fraclog_732log_78sqrt2 =left(log_8sqrt232right)=frac5frac72=frac107$$
edited Sep 7 at 10:05
answered Sep 7 at 9:47
Deepesh Meena
4,0162925
4,0162925
Thank you !!!!!
â Negrawh
Sep 8 at 11:30
add a comment |Â
Thank you !!!!!
â Negrawh
Sep 8 at 11:30
Thank you !!!!!
â Negrawh
Sep 8 at 11:30
Thank you !!!!!
â Negrawh
Sep 8 at 11:30
add a comment |Â
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BTW guys the x is times not 8x sorry!!
â Negrawh
Sep 7 at 9:39
It is $log_2^3 2^5 cdot sqrt 2$
â Mohammad Zuhair Khan
Sep 7 at 9:47
Is it $fraclog_732 log_78cdot sqrt2$ ?
â tarit goswami
Sep 7 at 9:47
Welcome to MathSE. Please read this MathJax tutorial, which explains how to typeset mathematics on this site. It is not clear whether you meant $fraclog_7 32log_7 8 cdot sqrt2$ or $fraclog_7 32log_7 8sqrt2$.
â N. F. Taussig
Sep 7 at 9:55
@N.F.Taussig I want the second one
â Negrawh
Sep 7 at 11:14