Solving an equation involving complex conjugates
I have the following question and cannot seem to overcome how to mix z and conjugate z together.
Find the value of $z in Bbb C$ that verifies the equation:
$$3z+ibar z=4+i$$
For other operations that didn't include mixing $z$ and $bar z$, I was able to manage by "isolating" $z$ on one side of the equation and finding the real and imaginary parts of the complex numbers (sorry if I'm not using the right terms, it's my first linear algebra course)
I tried with wolfram and it didn't really help.
PS: I'm new to this forum but if it's like other math forums where they send you to hell if you ask for "help with your homework", this "homework" I'm doing is on my own since my semester is over and I just wanted to explore other subjects in the book that weren't covered in class.
linear-algebra complex-numbers
New contributor
add a comment |
I have the following question and cannot seem to overcome how to mix z and conjugate z together.
Find the value of $z in Bbb C$ that verifies the equation:
$$3z+ibar z=4+i$$
For other operations that didn't include mixing $z$ and $bar z$, I was able to manage by "isolating" $z$ on one side of the equation and finding the real and imaginary parts of the complex numbers (sorry if I'm not using the right terms, it's my first linear algebra course)
I tried with wolfram and it didn't really help.
PS: I'm new to this forum but if it's like other math forums where they send you to hell if you ask for "help with your homework", this "homework" I'm doing is on my own since my semester is over and I just wanted to explore other subjects in the book that weren't covered in class.
linear-algebra complex-numbers
New contributor
1
Have you tried picking a basis for $mathbb{C}$, writing $z$ as a generic vector in that space using that basis, then solving for the components of $z$? I mean, ..., this is a linear algebra problem; why not "do the linear algebra thing" to it?
– Eric Towers
1 hour ago
add a comment |
I have the following question and cannot seem to overcome how to mix z and conjugate z together.
Find the value of $z in Bbb C$ that verifies the equation:
$$3z+ibar z=4+i$$
For other operations that didn't include mixing $z$ and $bar z$, I was able to manage by "isolating" $z$ on one side of the equation and finding the real and imaginary parts of the complex numbers (sorry if I'm not using the right terms, it's my first linear algebra course)
I tried with wolfram and it didn't really help.
PS: I'm new to this forum but if it's like other math forums where they send you to hell if you ask for "help with your homework", this "homework" I'm doing is on my own since my semester is over and I just wanted to explore other subjects in the book that weren't covered in class.
linear-algebra complex-numbers
New contributor
I have the following question and cannot seem to overcome how to mix z and conjugate z together.
Find the value of $z in Bbb C$ that verifies the equation:
$$3z+ibar z=4+i$$
For other operations that didn't include mixing $z$ and $bar z$, I was able to manage by "isolating" $z$ on one side of the equation and finding the real and imaginary parts of the complex numbers (sorry if I'm not using the right terms, it's my first linear algebra course)
I tried with wolfram and it didn't really help.
PS: I'm new to this forum but if it's like other math forums where they send you to hell if you ask for "help with your homework", this "homework" I'm doing is on my own since my semester is over and I just wanted to explore other subjects in the book that weren't covered in class.
linear-algebra complex-numbers
linear-algebra complex-numbers
New contributor
New contributor
edited 19 mins ago
Eevee Trainer
3,880428
3,880428
New contributor
asked 3 hours ago
Laura Salas
161
161
New contributor
New contributor
1
Have you tried picking a basis for $mathbb{C}$, writing $z$ as a generic vector in that space using that basis, then solving for the components of $z$? I mean, ..., this is a linear algebra problem; why not "do the linear algebra thing" to it?
– Eric Towers
1 hour ago
add a comment |
1
Have you tried picking a basis for $mathbb{C}$, writing $z$ as a generic vector in that space using that basis, then solving for the components of $z$? I mean, ..., this is a linear algebra problem; why not "do the linear algebra thing" to it?
– Eric Towers
1 hour ago
1
1
Have you tried picking a basis for $mathbb{C}$, writing $z$ as a generic vector in that space using that basis, then solving for the components of $z$? I mean, ..., this is a linear algebra problem; why not "do the linear algebra thing" to it?
– Eric Towers
1 hour ago
Have you tried picking a basis for $mathbb{C}$, writing $z$ as a generic vector in that space using that basis, then solving for the components of $z$? I mean, ..., this is a linear algebra problem; why not "do the linear algebra thing" to it?
– Eric Towers
1 hour ago
add a comment |
3 Answers
3
active
oldest
votes
Hint:
Let $z = x + iy$, for $x,y in mathbb{R}$. Consequently, $bar{z} = x - iy$.
Make these substitutions into your equation and isolate all of the $x$ and $y$ terms on one side, trying to make it "look" like a number in that form above (I really don't know how else to describe it, my example below will be more illustrative).
Equate the real and imaginary parts to get a system of equations in two variables ($x,y$) which you can solve get your solution.
Similar Exercise To Show What I Mean:
Let's solve for $z$ with
$$iz + 2bar{z} = 1 + 2i$$
Then, making our substitutions...
$$begin{align}
iz + 2bar{z} &= i(x + iy) + 2(x - iy) \
&= ix + i^2 y + 2x - 2iy \
&= ix - y + 2x - 2iy \
&= (2x - y) + i(x - 2y) \
end{align}$$
Thus,
$$ (2x - y) + i(x - 2y) = 1 + 2i$$
The real part of our left side is $2x-y$ and the imaginary part is $x - 2y$. On the right, the real and imaginary parts are $1$ and $2$ respectively.
Then, we get a system of equations by equating real and imaginary parts!
$$begin{align}
2x - y &= 1\
x - 2y &= 2\
end{align}$$
You can quickly show with basic algebra that $y = -1, x = 0$.
Our solution is a $z$ of the form $z = x + iy$. Thus, $z = 0 + i(-1) = -i$.
One Final Tidbit:
PS: I'm new to this forum but if it's like other math forums where they send you to hell if you ask for "help with your homework", this "homework" I'm doing is on my own since my semester is over and I just wanted to explore other subjects in the book that weren't covered in class.
This forum doesn't mind helping you with homework, so long as you show you make a reasonable effort or at least have a clear understanding of the material. However, the goal is also to help you learn, so people tend to prefer nudges in the right direction if the context allows it, as opposed to just handing you the solution. (Imagine how people would abuse the site for homework if every just gave the answers. Not good, and not what math is about, you get me?)
add a comment |
If $z=a+bi$ then $bar z=a-bi$
So you are solving:
$$3(a+bi)+i(a-bi)=4+i$$
$$to (3a+b)+(a+3b)i=4+i$$
Hence solve the simultaneous equations:
$$3a+b=4$$
$$a+3b=1$$
add a comment |
Let $a$ and $b$ be the real and imaginary parts of $z$. The equation becomes $$(3a+ib)+i(a-ib)=4+i$$
Equating real and imaginary parts you get $3a+b= 4$ and $3b+a=1$. Now you should be able to discover that $a=frac {11} 8$ and $b =-frac 1 8$, so $z=frac {11} 8-ifrac 1 8$.
1
It’s $3a + 3ib$ in the first bracket of your first equation.
– Live Free or π Hard
2 hours ago
add a comment |
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3 Answers
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3 Answers
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Hint:
Let $z = x + iy$, for $x,y in mathbb{R}$. Consequently, $bar{z} = x - iy$.
Make these substitutions into your equation and isolate all of the $x$ and $y$ terms on one side, trying to make it "look" like a number in that form above (I really don't know how else to describe it, my example below will be more illustrative).
Equate the real and imaginary parts to get a system of equations in two variables ($x,y$) which you can solve get your solution.
Similar Exercise To Show What I Mean:
Let's solve for $z$ with
$$iz + 2bar{z} = 1 + 2i$$
Then, making our substitutions...
$$begin{align}
iz + 2bar{z} &= i(x + iy) + 2(x - iy) \
&= ix + i^2 y + 2x - 2iy \
&= ix - y + 2x - 2iy \
&= (2x - y) + i(x - 2y) \
end{align}$$
Thus,
$$ (2x - y) + i(x - 2y) = 1 + 2i$$
The real part of our left side is $2x-y$ and the imaginary part is $x - 2y$. On the right, the real and imaginary parts are $1$ and $2$ respectively.
Then, we get a system of equations by equating real and imaginary parts!
$$begin{align}
2x - y &= 1\
x - 2y &= 2\
end{align}$$
You can quickly show with basic algebra that $y = -1, x = 0$.
Our solution is a $z$ of the form $z = x + iy$. Thus, $z = 0 + i(-1) = -i$.
One Final Tidbit:
PS: I'm new to this forum but if it's like other math forums where they send you to hell if you ask for "help with your homework", this "homework" I'm doing is on my own since my semester is over and I just wanted to explore other subjects in the book that weren't covered in class.
This forum doesn't mind helping you with homework, so long as you show you make a reasonable effort or at least have a clear understanding of the material. However, the goal is also to help you learn, so people tend to prefer nudges in the right direction if the context allows it, as opposed to just handing you the solution. (Imagine how people would abuse the site for homework if every just gave the answers. Not good, and not what math is about, you get me?)
add a comment |
Hint:
Let $z = x + iy$, for $x,y in mathbb{R}$. Consequently, $bar{z} = x - iy$.
Make these substitutions into your equation and isolate all of the $x$ and $y$ terms on one side, trying to make it "look" like a number in that form above (I really don't know how else to describe it, my example below will be more illustrative).
Equate the real and imaginary parts to get a system of equations in two variables ($x,y$) which you can solve get your solution.
Similar Exercise To Show What I Mean:
Let's solve for $z$ with
$$iz + 2bar{z} = 1 + 2i$$
Then, making our substitutions...
$$begin{align}
iz + 2bar{z} &= i(x + iy) + 2(x - iy) \
&= ix + i^2 y + 2x - 2iy \
&= ix - y + 2x - 2iy \
&= (2x - y) + i(x - 2y) \
end{align}$$
Thus,
$$ (2x - y) + i(x - 2y) = 1 + 2i$$
The real part of our left side is $2x-y$ and the imaginary part is $x - 2y$. On the right, the real and imaginary parts are $1$ and $2$ respectively.
Then, we get a system of equations by equating real and imaginary parts!
$$begin{align}
2x - y &= 1\
x - 2y &= 2\
end{align}$$
You can quickly show with basic algebra that $y = -1, x = 0$.
Our solution is a $z$ of the form $z = x + iy$. Thus, $z = 0 + i(-1) = -i$.
One Final Tidbit:
PS: I'm new to this forum but if it's like other math forums where they send you to hell if you ask for "help with your homework", this "homework" I'm doing is on my own since my semester is over and I just wanted to explore other subjects in the book that weren't covered in class.
This forum doesn't mind helping you with homework, so long as you show you make a reasonable effort or at least have a clear understanding of the material. However, the goal is also to help you learn, so people tend to prefer nudges in the right direction if the context allows it, as opposed to just handing you the solution. (Imagine how people would abuse the site for homework if every just gave the answers. Not good, and not what math is about, you get me?)
add a comment |
Hint:
Let $z = x + iy$, for $x,y in mathbb{R}$. Consequently, $bar{z} = x - iy$.
Make these substitutions into your equation and isolate all of the $x$ and $y$ terms on one side, trying to make it "look" like a number in that form above (I really don't know how else to describe it, my example below will be more illustrative).
Equate the real and imaginary parts to get a system of equations in two variables ($x,y$) which you can solve get your solution.
Similar Exercise To Show What I Mean:
Let's solve for $z$ with
$$iz + 2bar{z} = 1 + 2i$$
Then, making our substitutions...
$$begin{align}
iz + 2bar{z} &= i(x + iy) + 2(x - iy) \
&= ix + i^2 y + 2x - 2iy \
&= ix - y + 2x - 2iy \
&= (2x - y) + i(x - 2y) \
end{align}$$
Thus,
$$ (2x - y) + i(x - 2y) = 1 + 2i$$
The real part of our left side is $2x-y$ and the imaginary part is $x - 2y$. On the right, the real and imaginary parts are $1$ and $2$ respectively.
Then, we get a system of equations by equating real and imaginary parts!
$$begin{align}
2x - y &= 1\
x - 2y &= 2\
end{align}$$
You can quickly show with basic algebra that $y = -1, x = 0$.
Our solution is a $z$ of the form $z = x + iy$. Thus, $z = 0 + i(-1) = -i$.
One Final Tidbit:
PS: I'm new to this forum but if it's like other math forums where they send you to hell if you ask for "help with your homework", this "homework" I'm doing is on my own since my semester is over and I just wanted to explore other subjects in the book that weren't covered in class.
This forum doesn't mind helping you with homework, so long as you show you make a reasonable effort or at least have a clear understanding of the material. However, the goal is also to help you learn, so people tend to prefer nudges in the right direction if the context allows it, as opposed to just handing you the solution. (Imagine how people would abuse the site for homework if every just gave the answers. Not good, and not what math is about, you get me?)
Hint:
Let $z = x + iy$, for $x,y in mathbb{R}$. Consequently, $bar{z} = x - iy$.
Make these substitutions into your equation and isolate all of the $x$ and $y$ terms on one side, trying to make it "look" like a number in that form above (I really don't know how else to describe it, my example below will be more illustrative).
Equate the real and imaginary parts to get a system of equations in two variables ($x,y$) which you can solve get your solution.
Similar Exercise To Show What I Mean:
Let's solve for $z$ with
$$iz + 2bar{z} = 1 + 2i$$
Then, making our substitutions...
$$begin{align}
iz + 2bar{z} &= i(x + iy) + 2(x - iy) \
&= ix + i^2 y + 2x - 2iy \
&= ix - y + 2x - 2iy \
&= (2x - y) + i(x - 2y) \
end{align}$$
Thus,
$$ (2x - y) + i(x - 2y) = 1 + 2i$$
The real part of our left side is $2x-y$ and the imaginary part is $x - 2y$. On the right, the real and imaginary parts are $1$ and $2$ respectively.
Then, we get a system of equations by equating real and imaginary parts!
$$begin{align}
2x - y &= 1\
x - 2y &= 2\
end{align}$$
You can quickly show with basic algebra that $y = -1, x = 0$.
Our solution is a $z$ of the form $z = x + iy$. Thus, $z = 0 + i(-1) = -i$.
One Final Tidbit:
PS: I'm new to this forum but if it's like other math forums where they send you to hell if you ask for "help with your homework", this "homework" I'm doing is on my own since my semester is over and I just wanted to explore other subjects in the book that weren't covered in class.
This forum doesn't mind helping you with homework, so long as you show you make a reasonable effort or at least have a clear understanding of the material. However, the goal is also to help you learn, so people tend to prefer nudges in the right direction if the context allows it, as opposed to just handing you the solution. (Imagine how people would abuse the site for homework if every just gave the answers. Not good, and not what math is about, you get me?)
answered 2 hours ago
Eevee Trainer
3,880428
3,880428
add a comment |
add a comment |
If $z=a+bi$ then $bar z=a-bi$
So you are solving:
$$3(a+bi)+i(a-bi)=4+i$$
$$to (3a+b)+(a+3b)i=4+i$$
Hence solve the simultaneous equations:
$$3a+b=4$$
$$a+3b=1$$
add a comment |
If $z=a+bi$ then $bar z=a-bi$
So you are solving:
$$3(a+bi)+i(a-bi)=4+i$$
$$to (3a+b)+(a+3b)i=4+i$$
Hence solve the simultaneous equations:
$$3a+b=4$$
$$a+3b=1$$
add a comment |
If $z=a+bi$ then $bar z=a-bi$
So you are solving:
$$3(a+bi)+i(a-bi)=4+i$$
$$to (3a+b)+(a+3b)i=4+i$$
Hence solve the simultaneous equations:
$$3a+b=4$$
$$a+3b=1$$
If $z=a+bi$ then $bar z=a-bi$
So you are solving:
$$3(a+bi)+i(a-bi)=4+i$$
$$to (3a+b)+(a+3b)i=4+i$$
Hence solve the simultaneous equations:
$$3a+b=4$$
$$a+3b=1$$
answered 2 hours ago
Rhys Hughes
4,7511327
4,7511327
add a comment |
add a comment |
Let $a$ and $b$ be the real and imaginary parts of $z$. The equation becomes $$(3a+ib)+i(a-ib)=4+i$$
Equating real and imaginary parts you get $3a+b= 4$ and $3b+a=1$. Now you should be able to discover that $a=frac {11} 8$ and $b =-frac 1 8$, so $z=frac {11} 8-ifrac 1 8$.
1
It’s $3a + 3ib$ in the first bracket of your first equation.
– Live Free or π Hard
2 hours ago
add a comment |
Let $a$ and $b$ be the real and imaginary parts of $z$. The equation becomes $$(3a+ib)+i(a-ib)=4+i$$
Equating real and imaginary parts you get $3a+b= 4$ and $3b+a=1$. Now you should be able to discover that $a=frac {11} 8$ and $b =-frac 1 8$, so $z=frac {11} 8-ifrac 1 8$.
1
It’s $3a + 3ib$ in the first bracket of your first equation.
– Live Free or π Hard
2 hours ago
add a comment |
Let $a$ and $b$ be the real and imaginary parts of $z$. The equation becomes $$(3a+ib)+i(a-ib)=4+i$$
Equating real and imaginary parts you get $3a+b= 4$ and $3b+a=1$. Now you should be able to discover that $a=frac {11} 8$ and $b =-frac 1 8$, so $z=frac {11} 8-ifrac 1 8$.
Let $a$ and $b$ be the real and imaginary parts of $z$. The equation becomes $$(3a+ib)+i(a-ib)=4+i$$
Equating real and imaginary parts you get $3a+b= 4$ and $3b+a=1$. Now you should be able to discover that $a=frac {11} 8$ and $b =-frac 1 8$, so $z=frac {11} 8-ifrac 1 8$.
edited 2 hours ago
Eevee Trainer
3,880428
3,880428
answered 2 hours ago
Kavi Rama Murthy
49.4k31854
49.4k31854
1
It’s $3a + 3ib$ in the first bracket of your first equation.
– Live Free or π Hard
2 hours ago
add a comment |
1
It’s $3a + 3ib$ in the first bracket of your first equation.
– Live Free or π Hard
2 hours ago
1
1
It’s $3a + 3ib$ in the first bracket of your first equation.
– Live Free or π Hard
2 hours ago
It’s $3a + 3ib$ in the first bracket of your first equation.
– Live Free or π Hard
2 hours ago
add a comment |
Laura Salas is a new contributor. Be nice, and check out our Code of Conduct.
Laura Salas is a new contributor. Be nice, and check out our Code of Conduct.
Laura Salas is a new contributor. Be nice, and check out our Code of Conduct.
Laura Salas is a new contributor. Be nice, and check out our Code of Conduct.
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Have you tried picking a basis for $mathbb{C}$, writing $z$ as a generic vector in that space using that basis, then solving for the components of $z$? I mean, ..., this is a linear algebra problem; why not "do the linear algebra thing" to it?
– Eric Towers
1 hour ago