Evaluating $(sqrt{3}+i)^{2017} + (sqrt{3} - i)^{2017}$ [closed]
$begingroup$
I'm having a problem with following equation:
I'm applying $(a+b)^2$ and $(a-b)^2$, but am unable to get the correct answer.
$$(sqrt{3}+i)^{2017} + (sqrt{3} - i)^{2017}$$
calculus
$endgroup$
closed as off-topic by José Carlos Santos, Namaste, Nosrati, Saad, user10354138 Dec 23 '18 at 19:39
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, Namaste, Nosrati, Saad, user10354138
If this question can be reworded to fit the rules in the help center, please edit the question.
add a comment |
$begingroup$
I'm having a problem with following equation:
I'm applying $(a+b)^2$ and $(a-b)^2$, but am unable to get the correct answer.
$$(sqrt{3}+i)^{2017} + (sqrt{3} - i)^{2017}$$
calculus
$endgroup$
closed as off-topic by José Carlos Santos, Namaste, Nosrati, Saad, user10354138 Dec 23 '18 at 19:39
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, Namaste, Nosrati, Saad, user10354138
If this question can be reworded to fit the rules in the help center, please edit the question.
$begingroup$
What have you gotten? (Please include the work you've done, even if you found it doesn't yield the correct answer.) Alternatively, you may cite the source of the question, and explain why it is of interest to you and or the general community.
$endgroup$
– Namaste
Dec 23 '18 at 12:25
1
$begingroup$
Yeah my bad, it's my first post :). What i tried was to apply the basic rules of $(a+b)^2$ and $(a-b)^2$. So what i got is $$(sqrt{3}+i)^{2017} + (sqrt{3} - i)^{2017} = 3^{1008}sqrt{3} + 3^{1008}sqrt{3}$$ I'm not sure it's the correct way to approach with complex numbers. I used $(a+b)^3$, but that didn't seem right also.
$endgroup$
– arts
Dec 23 '18 at 12:35
add a comment |
$begingroup$
I'm having a problem with following equation:
I'm applying $(a+b)^2$ and $(a-b)^2$, but am unable to get the correct answer.
$$(sqrt{3}+i)^{2017} + (sqrt{3} - i)^{2017}$$
calculus
$endgroup$
I'm having a problem with following equation:
I'm applying $(a+b)^2$ and $(a-b)^2$, but am unable to get the correct answer.
$$(sqrt{3}+i)^{2017} + (sqrt{3} - i)^{2017}$$
calculus
calculus
edited Dec 23 '18 at 12:31
Blue
49.7k870158
49.7k870158
asked Dec 23 '18 at 12:13
artsarts
131
131
closed as off-topic by José Carlos Santos, Namaste, Nosrati, Saad, user10354138 Dec 23 '18 at 19:39
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, Namaste, Nosrati, Saad, user10354138
If this question can be reworded to fit the rules in the help center, please edit the question.
closed as off-topic by José Carlos Santos, Namaste, Nosrati, Saad, user10354138 Dec 23 '18 at 19:39
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, Namaste, Nosrati, Saad, user10354138
If this question can be reworded to fit the rules in the help center, please edit the question.
$begingroup$
What have you gotten? (Please include the work you've done, even if you found it doesn't yield the correct answer.) Alternatively, you may cite the source of the question, and explain why it is of interest to you and or the general community.
$endgroup$
– Namaste
Dec 23 '18 at 12:25
1
$begingroup$
Yeah my bad, it's my first post :). What i tried was to apply the basic rules of $(a+b)^2$ and $(a-b)^2$. So what i got is $$(sqrt{3}+i)^{2017} + (sqrt{3} - i)^{2017} = 3^{1008}sqrt{3} + 3^{1008}sqrt{3}$$ I'm not sure it's the correct way to approach with complex numbers. I used $(a+b)^3$, but that didn't seem right also.
$endgroup$
– arts
Dec 23 '18 at 12:35
add a comment |
$begingroup$
What have you gotten? (Please include the work you've done, even if you found it doesn't yield the correct answer.) Alternatively, you may cite the source of the question, and explain why it is of interest to you and or the general community.
$endgroup$
– Namaste
Dec 23 '18 at 12:25
1
$begingroup$
Yeah my bad, it's my first post :). What i tried was to apply the basic rules of $(a+b)^2$ and $(a-b)^2$. So what i got is $$(sqrt{3}+i)^{2017} + (sqrt{3} - i)^{2017} = 3^{1008}sqrt{3} + 3^{1008}sqrt{3}$$ I'm not sure it's the correct way to approach with complex numbers. I used $(a+b)^3$, but that didn't seem right also.
$endgroup$
– arts
Dec 23 '18 at 12:35
$begingroup$
What have you gotten? (Please include the work you've done, even if you found it doesn't yield the correct answer.) Alternatively, you may cite the source of the question, and explain why it is of interest to you and or the general community.
$endgroup$
– Namaste
Dec 23 '18 at 12:25
$begingroup$
What have you gotten? (Please include the work you've done, even if you found it doesn't yield the correct answer.) Alternatively, you may cite the source of the question, and explain why it is of interest to you and or the general community.
$endgroup$
– Namaste
Dec 23 '18 at 12:25
1
1
$begingroup$
Yeah my bad, it's my first post :). What i tried was to apply the basic rules of $(a+b)^2$ and $(a-b)^2$. So what i got is $$(sqrt{3}+i)^{2017} + (sqrt{3} - i)^{2017} = 3^{1008}sqrt{3} + 3^{1008}sqrt{3}$$ I'm not sure it's the correct way to approach with complex numbers. I used $(a+b)^3$, but that didn't seem right also.
$endgroup$
– arts
Dec 23 '18 at 12:35
$begingroup$
Yeah my bad, it's my first post :). What i tried was to apply the basic rules of $(a+b)^2$ and $(a-b)^2$. So what i got is $$(sqrt{3}+i)^{2017} + (sqrt{3} - i)^{2017} = 3^{1008}sqrt{3} + 3^{1008}sqrt{3}$$ I'm not sure it's the correct way to approach with complex numbers. I used $(a+b)^3$, but that didn't seem right also.
$endgroup$
– arts
Dec 23 '18 at 12:35
add a comment |
3 Answers
3
active
oldest
votes
$begingroup$
I would use the Euler's formula. Say $z = sqrt{3} + i$.
So $tan(phi) = 1/sqrt{3}$
and $phi = pi/6$
and $r = |z|= sqrt{1^2 + sqrt{3}^2} = sqrt{4} = 2$
Meaning $z = 2 cdot e^{i pi/6}$, $overline z = 2 cdot e^{-i pi/6}$
$z^{2017} = 2^2017 cdot e^{i cdot 2017 cdotpi/6}$, $(overline z)^{2017} = 2^{2017} cdot e^{-i cdot 2017 cdotpi/6}$
Converting this back from $w= |w| cdot e^{i cdot psi}$ to the form $w = a + ib$
with $Re(w) = a = |w|cos(psi)$ and $Im(w) = b = |w|sin(psi)$
gives us
$$z^{2017} + (overline z)^{2017} = \
Re(z^{2017}) + Re((overline z)^{2017}) + icdot (Im(z^{2017}) + Im((overline z)^{2017})) = \
2^{2017} cos(2017 cdot pi / 6) + 2^{2017} cos(- 2017 cdot pi /6) + icdot (2^{2017} sin(2017 cdot pi / 6) + 2^{2017} sin(- 2017 cdot pi / 6)) = \
2^{2017} cos(2017 cdot pi / 6) + 2^{2017} cos(2017 cdot pi /6) + icdot (2^{2017} sin(2017 cdot pi / 6) - 2^{2017} sin(2017 cdot pi / 6)) = \
2^{2017} (2 cdot cos(2017 cdot pi /6)) = \
2^{2017} (2 cdot cos(pi /6)) = \
2^{2017} (2 frac{sqrt{3}}{2}) = \
2^{2017} sqrt{3}
$$
$endgroup$
add a comment |
$begingroup$
Hint:
It's probably easier to write $sqrt 3+i=re^{itheta}$ and $sqrt 3-i=re^{-itheta}$, by finding $r,theta$, and then use $$rcos(theta)=rfrac{e^{itheta}+e^{-itheta}}{2}$$
$endgroup$
add a comment |
$begingroup$
Let $z=(sqrt 3 +i)^{2017}$, then $$z=2^{2017}e^{2017 ipi /6}$$
$$Re(z)=2^{2017}cos {2017pi /6} =2^{2017} cos {pi/6}$$
$z+bar z =2Re(z)=2^{2017}sqrt 3$
$endgroup$
$begingroup$
The exponent was supposed to be 2017 rather than 2007. In your case that means you get $Re(z) = 2^{2017} cos(2017 pi/6)$ which is $2^{2017} cos(pi /6) = 2^{2017} frac{sqrt{3}}{2}$
$endgroup$
– Coupeau
Dec 23 '18 at 14:50
$begingroup$
Thanks for the comment. I fixed my mistake
$endgroup$
– Mohammad Riazi-Kermani
Dec 23 '18 at 16:02
add a comment |
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
I would use the Euler's formula. Say $z = sqrt{3} + i$.
So $tan(phi) = 1/sqrt{3}$
and $phi = pi/6$
and $r = |z|= sqrt{1^2 + sqrt{3}^2} = sqrt{4} = 2$
Meaning $z = 2 cdot e^{i pi/6}$, $overline z = 2 cdot e^{-i pi/6}$
$z^{2017} = 2^2017 cdot e^{i cdot 2017 cdotpi/6}$, $(overline z)^{2017} = 2^{2017} cdot e^{-i cdot 2017 cdotpi/6}$
Converting this back from $w= |w| cdot e^{i cdot psi}$ to the form $w = a + ib$
with $Re(w) = a = |w|cos(psi)$ and $Im(w) = b = |w|sin(psi)$
gives us
$$z^{2017} + (overline z)^{2017} = \
Re(z^{2017}) + Re((overline z)^{2017}) + icdot (Im(z^{2017}) + Im((overline z)^{2017})) = \
2^{2017} cos(2017 cdot pi / 6) + 2^{2017} cos(- 2017 cdot pi /6) + icdot (2^{2017} sin(2017 cdot pi / 6) + 2^{2017} sin(- 2017 cdot pi / 6)) = \
2^{2017} cos(2017 cdot pi / 6) + 2^{2017} cos(2017 cdot pi /6) + icdot (2^{2017} sin(2017 cdot pi / 6) - 2^{2017} sin(2017 cdot pi / 6)) = \
2^{2017} (2 cdot cos(2017 cdot pi /6)) = \
2^{2017} (2 cdot cos(pi /6)) = \
2^{2017} (2 frac{sqrt{3}}{2}) = \
2^{2017} sqrt{3}
$$
$endgroup$
add a comment |
$begingroup$
I would use the Euler's formula. Say $z = sqrt{3} + i$.
So $tan(phi) = 1/sqrt{3}$
and $phi = pi/6$
and $r = |z|= sqrt{1^2 + sqrt{3}^2} = sqrt{4} = 2$
Meaning $z = 2 cdot e^{i pi/6}$, $overline z = 2 cdot e^{-i pi/6}$
$z^{2017} = 2^2017 cdot e^{i cdot 2017 cdotpi/6}$, $(overline z)^{2017} = 2^{2017} cdot e^{-i cdot 2017 cdotpi/6}$
Converting this back from $w= |w| cdot e^{i cdot psi}$ to the form $w = a + ib$
with $Re(w) = a = |w|cos(psi)$ and $Im(w) = b = |w|sin(psi)$
gives us
$$z^{2017} + (overline z)^{2017} = \
Re(z^{2017}) + Re((overline z)^{2017}) + icdot (Im(z^{2017}) + Im((overline z)^{2017})) = \
2^{2017} cos(2017 cdot pi / 6) + 2^{2017} cos(- 2017 cdot pi /6) + icdot (2^{2017} sin(2017 cdot pi / 6) + 2^{2017} sin(- 2017 cdot pi / 6)) = \
2^{2017} cos(2017 cdot pi / 6) + 2^{2017} cos(2017 cdot pi /6) + icdot (2^{2017} sin(2017 cdot pi / 6) - 2^{2017} sin(2017 cdot pi / 6)) = \
2^{2017} (2 cdot cos(2017 cdot pi /6)) = \
2^{2017} (2 cdot cos(pi /6)) = \
2^{2017} (2 frac{sqrt{3}}{2}) = \
2^{2017} sqrt{3}
$$
$endgroup$
add a comment |
$begingroup$
I would use the Euler's formula. Say $z = sqrt{3} + i$.
So $tan(phi) = 1/sqrt{3}$
and $phi = pi/6$
and $r = |z|= sqrt{1^2 + sqrt{3}^2} = sqrt{4} = 2$
Meaning $z = 2 cdot e^{i pi/6}$, $overline z = 2 cdot e^{-i pi/6}$
$z^{2017} = 2^2017 cdot e^{i cdot 2017 cdotpi/6}$, $(overline z)^{2017} = 2^{2017} cdot e^{-i cdot 2017 cdotpi/6}$
Converting this back from $w= |w| cdot e^{i cdot psi}$ to the form $w = a + ib$
with $Re(w) = a = |w|cos(psi)$ and $Im(w) = b = |w|sin(psi)$
gives us
$$z^{2017} + (overline z)^{2017} = \
Re(z^{2017}) + Re((overline z)^{2017}) + icdot (Im(z^{2017}) + Im((overline z)^{2017})) = \
2^{2017} cos(2017 cdot pi / 6) + 2^{2017} cos(- 2017 cdot pi /6) + icdot (2^{2017} sin(2017 cdot pi / 6) + 2^{2017} sin(- 2017 cdot pi / 6)) = \
2^{2017} cos(2017 cdot pi / 6) + 2^{2017} cos(2017 cdot pi /6) + icdot (2^{2017} sin(2017 cdot pi / 6) - 2^{2017} sin(2017 cdot pi / 6)) = \
2^{2017} (2 cdot cos(2017 cdot pi /6)) = \
2^{2017} (2 cdot cos(pi /6)) = \
2^{2017} (2 frac{sqrt{3}}{2}) = \
2^{2017} sqrt{3}
$$
$endgroup$
I would use the Euler's formula. Say $z = sqrt{3} + i$.
So $tan(phi) = 1/sqrt{3}$
and $phi = pi/6$
and $r = |z|= sqrt{1^2 + sqrt{3}^2} = sqrt{4} = 2$
Meaning $z = 2 cdot e^{i pi/6}$, $overline z = 2 cdot e^{-i pi/6}$
$z^{2017} = 2^2017 cdot e^{i cdot 2017 cdotpi/6}$, $(overline z)^{2017} = 2^{2017} cdot e^{-i cdot 2017 cdotpi/6}$
Converting this back from $w= |w| cdot e^{i cdot psi}$ to the form $w = a + ib$
with $Re(w) = a = |w|cos(psi)$ and $Im(w) = b = |w|sin(psi)$
gives us
$$z^{2017} + (overline z)^{2017} = \
Re(z^{2017}) + Re((overline z)^{2017}) + icdot (Im(z^{2017}) + Im((overline z)^{2017})) = \
2^{2017} cos(2017 cdot pi / 6) + 2^{2017} cos(- 2017 cdot pi /6) + icdot (2^{2017} sin(2017 cdot pi / 6) + 2^{2017} sin(- 2017 cdot pi / 6)) = \
2^{2017} cos(2017 cdot pi / 6) + 2^{2017} cos(2017 cdot pi /6) + icdot (2^{2017} sin(2017 cdot pi / 6) - 2^{2017} sin(2017 cdot pi / 6)) = \
2^{2017} (2 cdot cos(2017 cdot pi /6)) = \
2^{2017} (2 cdot cos(pi /6)) = \
2^{2017} (2 frac{sqrt{3}}{2}) = \
2^{2017} sqrt{3}
$$
edited Dec 23 '18 at 13:49
answered Dec 23 '18 at 13:28
CoupeauCoupeau
1296
1296
add a comment |
add a comment |
$begingroup$
Hint:
It's probably easier to write $sqrt 3+i=re^{itheta}$ and $sqrt 3-i=re^{-itheta}$, by finding $r,theta$, and then use $$rcos(theta)=rfrac{e^{itheta}+e^{-itheta}}{2}$$
$endgroup$
add a comment |
$begingroup$
Hint:
It's probably easier to write $sqrt 3+i=re^{itheta}$ and $sqrt 3-i=re^{-itheta}$, by finding $r,theta$, and then use $$rcos(theta)=rfrac{e^{itheta}+e^{-itheta}}{2}$$
$endgroup$
add a comment |
$begingroup$
Hint:
It's probably easier to write $sqrt 3+i=re^{itheta}$ and $sqrt 3-i=re^{-itheta}$, by finding $r,theta$, and then use $$rcos(theta)=rfrac{e^{itheta}+e^{-itheta}}{2}$$
$endgroup$
Hint:
It's probably easier to write $sqrt 3+i=re^{itheta}$ and $sqrt 3-i=re^{-itheta}$, by finding $r,theta$, and then use $$rcos(theta)=rfrac{e^{itheta}+e^{-itheta}}{2}$$
edited Dec 23 '18 at 12:20
mrtaurho
6,19771641
6,19771641
answered Dec 23 '18 at 12:19
cansomeonehelpmeoutcansomeonehelpmeout
7,3323935
7,3323935
add a comment |
add a comment |
$begingroup$
Let $z=(sqrt 3 +i)^{2017}$, then $$z=2^{2017}e^{2017 ipi /6}$$
$$Re(z)=2^{2017}cos {2017pi /6} =2^{2017} cos {pi/6}$$
$z+bar z =2Re(z)=2^{2017}sqrt 3$
$endgroup$
$begingroup$
The exponent was supposed to be 2017 rather than 2007. In your case that means you get $Re(z) = 2^{2017} cos(2017 pi/6)$ which is $2^{2017} cos(pi /6) = 2^{2017} frac{sqrt{3}}{2}$
$endgroup$
– Coupeau
Dec 23 '18 at 14:50
$begingroup$
Thanks for the comment. I fixed my mistake
$endgroup$
– Mohammad Riazi-Kermani
Dec 23 '18 at 16:02
add a comment |
$begingroup$
Let $z=(sqrt 3 +i)^{2017}$, then $$z=2^{2017}e^{2017 ipi /6}$$
$$Re(z)=2^{2017}cos {2017pi /6} =2^{2017} cos {pi/6}$$
$z+bar z =2Re(z)=2^{2017}sqrt 3$
$endgroup$
$begingroup$
The exponent was supposed to be 2017 rather than 2007. In your case that means you get $Re(z) = 2^{2017} cos(2017 pi/6)$ which is $2^{2017} cos(pi /6) = 2^{2017} frac{sqrt{3}}{2}$
$endgroup$
– Coupeau
Dec 23 '18 at 14:50
$begingroup$
Thanks for the comment. I fixed my mistake
$endgroup$
– Mohammad Riazi-Kermani
Dec 23 '18 at 16:02
add a comment |
$begingroup$
Let $z=(sqrt 3 +i)^{2017}$, then $$z=2^{2017}e^{2017 ipi /6}$$
$$Re(z)=2^{2017}cos {2017pi /6} =2^{2017} cos {pi/6}$$
$z+bar z =2Re(z)=2^{2017}sqrt 3$
$endgroup$
Let $z=(sqrt 3 +i)^{2017}$, then $$z=2^{2017}e^{2017 ipi /6}$$
$$Re(z)=2^{2017}cos {2017pi /6} =2^{2017} cos {pi/6}$$
$z+bar z =2Re(z)=2^{2017}sqrt 3$
edited Dec 23 '18 at 16:08
answered Dec 23 '18 at 13:27
Mohammad Riazi-KermaniMohammad Riazi-Kermani
42.2k42061
42.2k42061
$begingroup$
The exponent was supposed to be 2017 rather than 2007. In your case that means you get $Re(z) = 2^{2017} cos(2017 pi/6)$ which is $2^{2017} cos(pi /6) = 2^{2017} frac{sqrt{3}}{2}$
$endgroup$
– Coupeau
Dec 23 '18 at 14:50
$begingroup$
Thanks for the comment. I fixed my mistake
$endgroup$
– Mohammad Riazi-Kermani
Dec 23 '18 at 16:02
add a comment |
$begingroup$
The exponent was supposed to be 2017 rather than 2007. In your case that means you get $Re(z) = 2^{2017} cos(2017 pi/6)$ which is $2^{2017} cos(pi /6) = 2^{2017} frac{sqrt{3}}{2}$
$endgroup$
– Coupeau
Dec 23 '18 at 14:50
$begingroup$
Thanks for the comment. I fixed my mistake
$endgroup$
– Mohammad Riazi-Kermani
Dec 23 '18 at 16:02
$begingroup$
The exponent was supposed to be 2017 rather than 2007. In your case that means you get $Re(z) = 2^{2017} cos(2017 pi/6)$ which is $2^{2017} cos(pi /6) = 2^{2017} frac{sqrt{3}}{2}$
$endgroup$
– Coupeau
Dec 23 '18 at 14:50
$begingroup$
The exponent was supposed to be 2017 rather than 2007. In your case that means you get $Re(z) = 2^{2017} cos(2017 pi/6)$ which is $2^{2017} cos(pi /6) = 2^{2017} frac{sqrt{3}}{2}$
$endgroup$
– Coupeau
Dec 23 '18 at 14:50
$begingroup$
Thanks for the comment. I fixed my mistake
$endgroup$
– Mohammad Riazi-Kermani
Dec 23 '18 at 16:02
$begingroup$
Thanks for the comment. I fixed my mistake
$endgroup$
– Mohammad Riazi-Kermani
Dec 23 '18 at 16:02
add a comment |
$begingroup$
What have you gotten? (Please include the work you've done, even if you found it doesn't yield the correct answer.) Alternatively, you may cite the source of the question, and explain why it is of interest to you and or the general community.
$endgroup$
– Namaste
Dec 23 '18 at 12:25
1
$begingroup$
Yeah my bad, it's my first post :). What i tried was to apply the basic rules of $(a+b)^2$ and $(a-b)^2$. So what i got is $$(sqrt{3}+i)^{2017} + (sqrt{3} - i)^{2017} = 3^{1008}sqrt{3} + 3^{1008}sqrt{3}$$ I'm not sure it's the correct way to approach with complex numbers. I used $(a+b)^3$, but that didn't seem right also.
$endgroup$
– arts
Dec 23 '18 at 12:35