If $z_1,z_2$ satisfy $z+bar{z}=2|z-1|$, $arg(z_1-z_2)=dfrac{pi}{4}$, then find $Im(z_1+z_2)$
$begingroup$
If $z_1$ and $z_2$ both satisfy $z+bar{z}=2|z-1|$, $arg(z_1-z_2)=dfrac{pi}{4}$, then find $Im(z_1+z_2)$
My Attempt
$$
z_1+bar{z}_1=2|z_1-1|quad&quad z_2+bar{z}_2=2|z_2-1|quad&quad arg(z_1-z_2)=dfrac{pi}{4}\
z_1-z_2=frac{|z_1-z_2|}{sqrt{2}}Big(1+iBig)\
Re(z_1+z_2)=frac{z_1+z_2+bar{z}_1+bar{z}_2}{2}=|z_1-1|+|z_2-1|\
Im(z_1+z_2)=frac{z_1+z_2-bar{z}_1-bar{z}_2}{2i}\
Re(z_1-z_2)=frac{z_1-z_2+bar{z}_1-bar{z}_2}{2}=frac{|z_1-z_2|}{sqrt{2}}={|z_1-1|-|z_2-1|}\
Im(z_1-z_2)=frac{z_1-z_2-bar{z}_1+bar{z}_2}{2i}=frac{|z_1-z_2|}{sqrt{2}}
$$
My reference gives the solution $2$, but how do I find the solution without actually representing $z=a+ib$ ?
complex-numbers
$endgroup$
add a comment |
$begingroup$
If $z_1$ and $z_2$ both satisfy $z+bar{z}=2|z-1|$, $arg(z_1-z_2)=dfrac{pi}{4}$, then find $Im(z_1+z_2)$
My Attempt
$$
z_1+bar{z}_1=2|z_1-1|quad&quad z_2+bar{z}_2=2|z_2-1|quad&quad arg(z_1-z_2)=dfrac{pi}{4}\
z_1-z_2=frac{|z_1-z_2|}{sqrt{2}}Big(1+iBig)\
Re(z_1+z_2)=frac{z_1+z_2+bar{z}_1+bar{z}_2}{2}=|z_1-1|+|z_2-1|\
Im(z_1+z_2)=frac{z_1+z_2-bar{z}_1-bar{z}_2}{2i}\
Re(z_1-z_2)=frac{z_1-z_2+bar{z}_1-bar{z}_2}{2}=frac{|z_1-z_2|}{sqrt{2}}={|z_1-1|-|z_2-1|}\
Im(z_1-z_2)=frac{z_1-z_2-bar{z}_1+bar{z}_2}{2i}=frac{|z_1-z_2|}{sqrt{2}}
$$
My reference gives the solution $2$, but how do I find the solution without actually representing $z=a+ib$ ?
complex-numbers
$endgroup$
add a comment |
$begingroup$
If $z_1$ and $z_2$ both satisfy $z+bar{z}=2|z-1|$, $arg(z_1-z_2)=dfrac{pi}{4}$, then find $Im(z_1+z_2)$
My Attempt
$$
z_1+bar{z}_1=2|z_1-1|quad&quad z_2+bar{z}_2=2|z_2-1|quad&quad arg(z_1-z_2)=dfrac{pi}{4}\
z_1-z_2=frac{|z_1-z_2|}{sqrt{2}}Big(1+iBig)\
Re(z_1+z_2)=frac{z_1+z_2+bar{z}_1+bar{z}_2}{2}=|z_1-1|+|z_2-1|\
Im(z_1+z_2)=frac{z_1+z_2-bar{z}_1-bar{z}_2}{2i}\
Re(z_1-z_2)=frac{z_1-z_2+bar{z}_1-bar{z}_2}{2}=frac{|z_1-z_2|}{sqrt{2}}={|z_1-1|-|z_2-1|}\
Im(z_1-z_2)=frac{z_1-z_2-bar{z}_1+bar{z}_2}{2i}=frac{|z_1-z_2|}{sqrt{2}}
$$
My reference gives the solution $2$, but how do I find the solution without actually representing $z=a+ib$ ?
complex-numbers
$endgroup$
If $z_1$ and $z_2$ both satisfy $z+bar{z}=2|z-1|$, $arg(z_1-z_2)=dfrac{pi}{4}$, then find $Im(z_1+z_2)$
My Attempt
$$
z_1+bar{z}_1=2|z_1-1|quad&quad z_2+bar{z}_2=2|z_2-1|quad&quad arg(z_1-z_2)=dfrac{pi}{4}\
z_1-z_2=frac{|z_1-z_2|}{sqrt{2}}Big(1+iBig)\
Re(z_1+z_2)=frac{z_1+z_2+bar{z}_1+bar{z}_2}{2}=|z_1-1|+|z_2-1|\
Im(z_1+z_2)=frac{z_1+z_2-bar{z}_1-bar{z}_2}{2i}\
Re(z_1-z_2)=frac{z_1-z_2+bar{z}_1-bar{z}_2}{2}=frac{|z_1-z_2|}{sqrt{2}}={|z_1-1|-|z_2-1|}\
Im(z_1-z_2)=frac{z_1-z_2-bar{z}_1+bar{z}_2}{2i}=frac{|z_1-z_2|}{sqrt{2}}
$$
My reference gives the solution $2$, but how do I find the solution without actually representing $z=a+ib$ ?
complex-numbers
complex-numbers
edited Jan 9 at 6:56
ss1729
asked Jan 8 at 10:07
ss1729ss1729
2,07811124
2,07811124
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
It's easy if you consider
$z_1=a_1+ib_1$ , $z_2=a_2+ib_2$
$bar{z_1}=a_1-ib_1$ , $bar{z_2}=a_2-ib_2$
Given $z+bar{z}=2|z-1|$
Since, $z_1$ and $z_2$ both satisfy, $z+bar{z}=2|z-1|$, we can say that $$z_1+bar{z_1}=2|z_1-1|$$ and $$z_2+bar{z_2}=2|z_2-1|$$
Firstly, $$z_1+bar{z_1}=2|z_1-1|$$
$$a_1+ib_1+a_1-ib_1=2|(a_1-1)+ib_1|$$
After solving we get, $$b_1^2=2a_1-1tag1$$
Similarly, we get $$b_1^2=2a_2-1tag3$$
Now, $$arg(z_1-z_2)=dfrac{pi}{4}$$
$$arg(a_1+ib_1-a_2-ib_2)=dfrac{pi}{4}$$
$$dfrac{b_1-b_2}{a_1-a_2}=tandfrac{pi}{4}$$
$$dfrac{b_1-b_2}{a_1-a_2}=1$$
$$b_1-b_2=a_1-a_2tag3$$
Now use the equations $(1),(2)$ and $(3)$ to get the final answer.
$endgroup$
add a comment |
$begingroup$
Without representing $z=a+bi$.
begin{align}
z+bar z&=2|z-1|\
(z+bar z)^2&=4|z-1|^2=4(z-1)(bar z-1)\
z^2+2zbar z+bar z^2&=4(zbar z-z-bar z+1)\
z^2-2zbar z+bar z^2&=4-4(z+bar z)\
(z-bar z)^2&=4-4(z+bar z)tag{1}
end{align}
Now take (1) for $z_2$ minus (1) for $z_1$ and use
$$
z_1-z_2=frac{|z_1-z_2|}{sqrt{2}}(1+i)tag{2}
$$
to get
begin{align}
(z_2-bar z_2)^2-(z_1-bar z_1)^2&=4(z_1+bar z_1-z_2-bar z_2)\
(underbrace{z_2-bar z_2-z_1+bar z_1}_{-sqrt2i|z_1-z_2|})(underbrace{z_2-bar z_2+z_1-bar z_1}_{2ioperatorname{Im}(z_1+z_2)})&=4(underbrace{z_1+bar z_1-z_2-bar z_2}_{sqrt2|z_1-z_2|})\
|z_1-z_2|(operatorname{Im}(z_1+z_2)-2)&=0.
end{align}
$endgroup$
add a comment |
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2 Answers
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2 Answers
2
active
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$begingroup$
It's easy if you consider
$z_1=a_1+ib_1$ , $z_2=a_2+ib_2$
$bar{z_1}=a_1-ib_1$ , $bar{z_2}=a_2-ib_2$
Given $z+bar{z}=2|z-1|$
Since, $z_1$ and $z_2$ both satisfy, $z+bar{z}=2|z-1|$, we can say that $$z_1+bar{z_1}=2|z_1-1|$$ and $$z_2+bar{z_2}=2|z_2-1|$$
Firstly, $$z_1+bar{z_1}=2|z_1-1|$$
$$a_1+ib_1+a_1-ib_1=2|(a_1-1)+ib_1|$$
After solving we get, $$b_1^2=2a_1-1tag1$$
Similarly, we get $$b_1^2=2a_2-1tag3$$
Now, $$arg(z_1-z_2)=dfrac{pi}{4}$$
$$arg(a_1+ib_1-a_2-ib_2)=dfrac{pi}{4}$$
$$dfrac{b_1-b_2}{a_1-a_2}=tandfrac{pi}{4}$$
$$dfrac{b_1-b_2}{a_1-a_2}=1$$
$$b_1-b_2=a_1-a_2tag3$$
Now use the equations $(1),(2)$ and $(3)$ to get the final answer.
$endgroup$
add a comment |
$begingroup$
It's easy if you consider
$z_1=a_1+ib_1$ , $z_2=a_2+ib_2$
$bar{z_1}=a_1-ib_1$ , $bar{z_2}=a_2-ib_2$
Given $z+bar{z}=2|z-1|$
Since, $z_1$ and $z_2$ both satisfy, $z+bar{z}=2|z-1|$, we can say that $$z_1+bar{z_1}=2|z_1-1|$$ and $$z_2+bar{z_2}=2|z_2-1|$$
Firstly, $$z_1+bar{z_1}=2|z_1-1|$$
$$a_1+ib_1+a_1-ib_1=2|(a_1-1)+ib_1|$$
After solving we get, $$b_1^2=2a_1-1tag1$$
Similarly, we get $$b_1^2=2a_2-1tag3$$
Now, $$arg(z_1-z_2)=dfrac{pi}{4}$$
$$arg(a_1+ib_1-a_2-ib_2)=dfrac{pi}{4}$$
$$dfrac{b_1-b_2}{a_1-a_2}=tandfrac{pi}{4}$$
$$dfrac{b_1-b_2}{a_1-a_2}=1$$
$$b_1-b_2=a_1-a_2tag3$$
Now use the equations $(1),(2)$ and $(3)$ to get the final answer.
$endgroup$
add a comment |
$begingroup$
It's easy if you consider
$z_1=a_1+ib_1$ , $z_2=a_2+ib_2$
$bar{z_1}=a_1-ib_1$ , $bar{z_2}=a_2-ib_2$
Given $z+bar{z}=2|z-1|$
Since, $z_1$ and $z_2$ both satisfy, $z+bar{z}=2|z-1|$, we can say that $$z_1+bar{z_1}=2|z_1-1|$$ and $$z_2+bar{z_2}=2|z_2-1|$$
Firstly, $$z_1+bar{z_1}=2|z_1-1|$$
$$a_1+ib_1+a_1-ib_1=2|(a_1-1)+ib_1|$$
After solving we get, $$b_1^2=2a_1-1tag1$$
Similarly, we get $$b_1^2=2a_2-1tag3$$
Now, $$arg(z_1-z_2)=dfrac{pi}{4}$$
$$arg(a_1+ib_1-a_2-ib_2)=dfrac{pi}{4}$$
$$dfrac{b_1-b_2}{a_1-a_2}=tandfrac{pi}{4}$$
$$dfrac{b_1-b_2}{a_1-a_2}=1$$
$$b_1-b_2=a_1-a_2tag3$$
Now use the equations $(1),(2)$ and $(3)$ to get the final answer.
$endgroup$
It's easy if you consider
$z_1=a_1+ib_1$ , $z_2=a_2+ib_2$
$bar{z_1}=a_1-ib_1$ , $bar{z_2}=a_2-ib_2$
Given $z+bar{z}=2|z-1|$
Since, $z_1$ and $z_2$ both satisfy, $z+bar{z}=2|z-1|$, we can say that $$z_1+bar{z_1}=2|z_1-1|$$ and $$z_2+bar{z_2}=2|z_2-1|$$
Firstly, $$z_1+bar{z_1}=2|z_1-1|$$
$$a_1+ib_1+a_1-ib_1=2|(a_1-1)+ib_1|$$
After solving we get, $$b_1^2=2a_1-1tag1$$
Similarly, we get $$b_1^2=2a_2-1tag3$$
Now, $$arg(z_1-z_2)=dfrac{pi}{4}$$
$$arg(a_1+ib_1-a_2-ib_2)=dfrac{pi}{4}$$
$$dfrac{b_1-b_2}{a_1-a_2}=tandfrac{pi}{4}$$
$$dfrac{b_1-b_2}{a_1-a_2}=1$$
$$b_1-b_2=a_1-a_2tag3$$
Now use the equations $(1),(2)$ and $(3)$ to get the final answer.
answered Jan 8 at 10:33
Key FlexKey Flex
8,56171233
8,56171233
add a comment |
add a comment |
$begingroup$
Without representing $z=a+bi$.
begin{align}
z+bar z&=2|z-1|\
(z+bar z)^2&=4|z-1|^2=4(z-1)(bar z-1)\
z^2+2zbar z+bar z^2&=4(zbar z-z-bar z+1)\
z^2-2zbar z+bar z^2&=4-4(z+bar z)\
(z-bar z)^2&=4-4(z+bar z)tag{1}
end{align}
Now take (1) for $z_2$ minus (1) for $z_1$ and use
$$
z_1-z_2=frac{|z_1-z_2|}{sqrt{2}}(1+i)tag{2}
$$
to get
begin{align}
(z_2-bar z_2)^2-(z_1-bar z_1)^2&=4(z_1+bar z_1-z_2-bar z_2)\
(underbrace{z_2-bar z_2-z_1+bar z_1}_{-sqrt2i|z_1-z_2|})(underbrace{z_2-bar z_2+z_1-bar z_1}_{2ioperatorname{Im}(z_1+z_2)})&=4(underbrace{z_1+bar z_1-z_2-bar z_2}_{sqrt2|z_1-z_2|})\
|z_1-z_2|(operatorname{Im}(z_1+z_2)-2)&=0.
end{align}
$endgroup$
add a comment |
$begingroup$
Without representing $z=a+bi$.
begin{align}
z+bar z&=2|z-1|\
(z+bar z)^2&=4|z-1|^2=4(z-1)(bar z-1)\
z^2+2zbar z+bar z^2&=4(zbar z-z-bar z+1)\
z^2-2zbar z+bar z^2&=4-4(z+bar z)\
(z-bar z)^2&=4-4(z+bar z)tag{1}
end{align}
Now take (1) for $z_2$ minus (1) for $z_1$ and use
$$
z_1-z_2=frac{|z_1-z_2|}{sqrt{2}}(1+i)tag{2}
$$
to get
begin{align}
(z_2-bar z_2)^2-(z_1-bar z_1)^2&=4(z_1+bar z_1-z_2-bar z_2)\
(underbrace{z_2-bar z_2-z_1+bar z_1}_{-sqrt2i|z_1-z_2|})(underbrace{z_2-bar z_2+z_1-bar z_1}_{2ioperatorname{Im}(z_1+z_2)})&=4(underbrace{z_1+bar z_1-z_2-bar z_2}_{sqrt2|z_1-z_2|})\
|z_1-z_2|(operatorname{Im}(z_1+z_2)-2)&=0.
end{align}
$endgroup$
add a comment |
$begingroup$
Without representing $z=a+bi$.
begin{align}
z+bar z&=2|z-1|\
(z+bar z)^2&=4|z-1|^2=4(z-1)(bar z-1)\
z^2+2zbar z+bar z^2&=4(zbar z-z-bar z+1)\
z^2-2zbar z+bar z^2&=4-4(z+bar z)\
(z-bar z)^2&=4-4(z+bar z)tag{1}
end{align}
Now take (1) for $z_2$ minus (1) for $z_1$ and use
$$
z_1-z_2=frac{|z_1-z_2|}{sqrt{2}}(1+i)tag{2}
$$
to get
begin{align}
(z_2-bar z_2)^2-(z_1-bar z_1)^2&=4(z_1+bar z_1-z_2-bar z_2)\
(underbrace{z_2-bar z_2-z_1+bar z_1}_{-sqrt2i|z_1-z_2|})(underbrace{z_2-bar z_2+z_1-bar z_1}_{2ioperatorname{Im}(z_1+z_2)})&=4(underbrace{z_1+bar z_1-z_2-bar z_2}_{sqrt2|z_1-z_2|})\
|z_1-z_2|(operatorname{Im}(z_1+z_2)-2)&=0.
end{align}
$endgroup$
Without representing $z=a+bi$.
begin{align}
z+bar z&=2|z-1|\
(z+bar z)^2&=4|z-1|^2=4(z-1)(bar z-1)\
z^2+2zbar z+bar z^2&=4(zbar z-z-bar z+1)\
z^2-2zbar z+bar z^2&=4-4(z+bar z)\
(z-bar z)^2&=4-4(z+bar z)tag{1}
end{align}
Now take (1) for $z_2$ minus (1) for $z_1$ and use
$$
z_1-z_2=frac{|z_1-z_2|}{sqrt{2}}(1+i)tag{2}
$$
to get
begin{align}
(z_2-bar z_2)^2-(z_1-bar z_1)^2&=4(z_1+bar z_1-z_2-bar z_2)\
(underbrace{z_2-bar z_2-z_1+bar z_1}_{-sqrt2i|z_1-z_2|})(underbrace{z_2-bar z_2+z_1-bar z_1}_{2ioperatorname{Im}(z_1+z_2)})&=4(underbrace{z_1+bar z_1-z_2-bar z_2}_{sqrt2|z_1-z_2|})\
|z_1-z_2|(operatorname{Im}(z_1+z_2)-2)&=0.
end{align}
answered Jan 8 at 12:48
A.Γ.A.Γ.
22.9k32656
22.9k32656
add a comment |
add a comment |
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