Show that $|{|2overline{z}+5 |(sqrt2 - i)} | = sqrt3 |2z+5|$, where z is a complex number.











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Show that $|{|2overline{z}+5 |(sqrt2 - i)} | = sqrt3 |2z+5|$, where z is a complex number.



And $overline{z}$ is complex conjugate of $z$.



And $i$ is iota.



I'm proceeding by considering $z=x+iy$



But I just get stuck at different results approaching different ways.
Please help.










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  • |ab|= |a||b|, a,b complex.LHS: $√3|2overline{z}+5|$.Then $|a|=|overline{a}|$.Helps?
    – Peter Szilas
    Nov 21 at 13:46












  • @PeterSzilas I didn't understand, how can you bring LHS as $sqrt3|2overline{z}+5|$ . I mean how did you proceed with the LHS to get that!?
    – Kaustuv Sawarn
    Nov 21 at 13:57












  • Kaustuv.$|√2-i|=sqrt{(√2)^2+i^2}=sqrt{4-1} =√3.$Ok?
    – Peter Szilas
    Nov 21 at 16:12












  • @PeterSzilas yes. I got it. Thanks!
    – Kaustuv Sawarn
    Nov 21 at 16:29










  • Kaustuv.Welcome:)
    – Peter Szilas
    Nov 21 at 16:35















up vote
-1
down vote

favorite












Show that $|{|2overline{z}+5 |(sqrt2 - i)} | = sqrt3 |2z+5|$, where z is a complex number.



And $overline{z}$ is complex conjugate of $z$.



And $i$ is iota.



I'm proceeding by considering $z=x+iy$



But I just get stuck at different results approaching different ways.
Please help.










share|cite|improve this question






















  • |ab|= |a||b|, a,b complex.LHS: $√3|2overline{z}+5|$.Then $|a|=|overline{a}|$.Helps?
    – Peter Szilas
    Nov 21 at 13:46












  • @PeterSzilas I didn't understand, how can you bring LHS as $sqrt3|2overline{z}+5|$ . I mean how did you proceed with the LHS to get that!?
    – Kaustuv Sawarn
    Nov 21 at 13:57












  • Kaustuv.$|√2-i|=sqrt{(√2)^2+i^2}=sqrt{4-1} =√3.$Ok?
    – Peter Szilas
    Nov 21 at 16:12












  • @PeterSzilas yes. I got it. Thanks!
    – Kaustuv Sawarn
    Nov 21 at 16:29










  • Kaustuv.Welcome:)
    – Peter Szilas
    Nov 21 at 16:35













up vote
-1
down vote

favorite









up vote
-1
down vote

favorite











Show that $|{|2overline{z}+5 |(sqrt2 - i)} | = sqrt3 |2z+5|$, where z is a complex number.



And $overline{z}$ is complex conjugate of $z$.



And $i$ is iota.



I'm proceeding by considering $z=x+iy$



But I just get stuck at different results approaching different ways.
Please help.










share|cite|improve this question













Show that $|{|2overline{z}+5 |(sqrt2 - i)} | = sqrt3 |2z+5|$, where z is a complex number.



And $overline{z}$ is complex conjugate of $z$.



And $i$ is iota.



I'm proceeding by considering $z=x+iy$



But I just get stuck at different results approaching different ways.
Please help.







complex-analysis complex-numbers






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share|cite|improve this question











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asked Nov 21 at 13:40









Kaustuv Sawarn

465




465












  • |ab|= |a||b|, a,b complex.LHS: $√3|2overline{z}+5|$.Then $|a|=|overline{a}|$.Helps?
    – Peter Szilas
    Nov 21 at 13:46












  • @PeterSzilas I didn't understand, how can you bring LHS as $sqrt3|2overline{z}+5|$ . I mean how did you proceed with the LHS to get that!?
    – Kaustuv Sawarn
    Nov 21 at 13:57












  • Kaustuv.$|√2-i|=sqrt{(√2)^2+i^2}=sqrt{4-1} =√3.$Ok?
    – Peter Szilas
    Nov 21 at 16:12












  • @PeterSzilas yes. I got it. Thanks!
    – Kaustuv Sawarn
    Nov 21 at 16:29










  • Kaustuv.Welcome:)
    – Peter Szilas
    Nov 21 at 16:35


















  • |ab|= |a||b|, a,b complex.LHS: $√3|2overline{z}+5|$.Then $|a|=|overline{a}|$.Helps?
    – Peter Szilas
    Nov 21 at 13:46












  • @PeterSzilas I didn't understand, how can you bring LHS as $sqrt3|2overline{z}+5|$ . I mean how did you proceed with the LHS to get that!?
    – Kaustuv Sawarn
    Nov 21 at 13:57












  • Kaustuv.$|√2-i|=sqrt{(√2)^2+i^2}=sqrt{4-1} =√3.$Ok?
    – Peter Szilas
    Nov 21 at 16:12












  • @PeterSzilas yes. I got it. Thanks!
    – Kaustuv Sawarn
    Nov 21 at 16:29










  • Kaustuv.Welcome:)
    – Peter Szilas
    Nov 21 at 16:35
















|ab|= |a||b|, a,b complex.LHS: $√3|2overline{z}+5|$.Then $|a|=|overline{a}|$.Helps?
– Peter Szilas
Nov 21 at 13:46






|ab|= |a||b|, a,b complex.LHS: $√3|2overline{z}+5|$.Then $|a|=|overline{a}|$.Helps?
– Peter Szilas
Nov 21 at 13:46














@PeterSzilas I didn't understand, how can you bring LHS as $sqrt3|2overline{z}+5|$ . I mean how did you proceed with the LHS to get that!?
– Kaustuv Sawarn
Nov 21 at 13:57






@PeterSzilas I didn't understand, how can you bring LHS as $sqrt3|2overline{z}+5|$ . I mean how did you proceed with the LHS to get that!?
– Kaustuv Sawarn
Nov 21 at 13:57














Kaustuv.$|√2-i|=sqrt{(√2)^2+i^2}=sqrt{4-1} =√3.$Ok?
– Peter Szilas
Nov 21 at 16:12






Kaustuv.$|√2-i|=sqrt{(√2)^2+i^2}=sqrt{4-1} =√3.$Ok?
– Peter Szilas
Nov 21 at 16:12














@PeterSzilas yes. I got it. Thanks!
– Kaustuv Sawarn
Nov 21 at 16:29




@PeterSzilas yes. I got it. Thanks!
– Kaustuv Sawarn
Nov 21 at 16:29












Kaustuv.Welcome:)
– Peter Szilas
Nov 21 at 16:35




Kaustuv.Welcome:)
– Peter Szilas
Nov 21 at 16:35










1 Answer
1






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1
down vote



accepted










LHS is $||2overline{z}+5|cdot(sqrt2 - i)|$; and $a=|2overline{z}+5| geq 0$. Then
$$||2overline{z}+5|cdot(sqrt2 - i)|=|acdot(sqrt2 - i)|=|a|cdot|sqrt2 - i|\=sqrt3 cdot a=sqrt3 cdot |2overline{z}+5|=sqrt3 cdot |overline{2z+5}|$$






share|cite|improve this answer























  • I think this is a silly question but how is $|sqrt2-i| = sqrt3$
    – Kaustuv Sawarn
    Nov 21 at 14:31












  • $|a+ib| = sqrt{a^2 + b^2}$, where $z = a+ib$. In this case, $a = sqrt2, b = -1$
    – Naweed G. Seldon
    Nov 21 at 14:36












  • haha, damn. I didn't even think like that! Thankyou very much!!
    – Kaustuv Sawarn
    Nov 21 at 15:03











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LHS is $||2overline{z}+5|cdot(sqrt2 - i)|$; and $a=|2overline{z}+5| geq 0$. Then
$$||2overline{z}+5|cdot(sqrt2 - i)|=|acdot(sqrt2 - i)|=|a|cdot|sqrt2 - i|\=sqrt3 cdot a=sqrt3 cdot |2overline{z}+5|=sqrt3 cdot |overline{2z+5}|$$






share|cite|improve this answer























  • I think this is a silly question but how is $|sqrt2-i| = sqrt3$
    – Kaustuv Sawarn
    Nov 21 at 14:31












  • $|a+ib| = sqrt{a^2 + b^2}$, where $z = a+ib$. In this case, $a = sqrt2, b = -1$
    – Naweed G. Seldon
    Nov 21 at 14:36












  • haha, damn. I didn't even think like that! Thankyou very much!!
    – Kaustuv Sawarn
    Nov 21 at 15:03















up vote
1
down vote



accepted










LHS is $||2overline{z}+5|cdot(sqrt2 - i)|$; and $a=|2overline{z}+5| geq 0$. Then
$$||2overline{z}+5|cdot(sqrt2 - i)|=|acdot(sqrt2 - i)|=|a|cdot|sqrt2 - i|\=sqrt3 cdot a=sqrt3 cdot |2overline{z}+5|=sqrt3 cdot |overline{2z+5}|$$






share|cite|improve this answer























  • I think this is a silly question but how is $|sqrt2-i| = sqrt3$
    – Kaustuv Sawarn
    Nov 21 at 14:31












  • $|a+ib| = sqrt{a^2 + b^2}$, where $z = a+ib$. In this case, $a = sqrt2, b = -1$
    – Naweed G. Seldon
    Nov 21 at 14:36












  • haha, damn. I didn't even think like that! Thankyou very much!!
    – Kaustuv Sawarn
    Nov 21 at 15:03













up vote
1
down vote



accepted







up vote
1
down vote



accepted






LHS is $||2overline{z}+5|cdot(sqrt2 - i)|$; and $a=|2overline{z}+5| geq 0$. Then
$$||2overline{z}+5|cdot(sqrt2 - i)|=|acdot(sqrt2 - i)|=|a|cdot|sqrt2 - i|\=sqrt3 cdot a=sqrt3 cdot |2overline{z}+5|=sqrt3 cdot |overline{2z+5}|$$






share|cite|improve this answer














LHS is $||2overline{z}+5|cdot(sqrt2 - i)|$; and $a=|2overline{z}+5| geq 0$. Then
$$||2overline{z}+5|cdot(sqrt2 - i)|=|acdot(sqrt2 - i)|=|a|cdot|sqrt2 - i|\=sqrt3 cdot a=sqrt3 cdot |2overline{z}+5|=sqrt3 cdot |overline{2z+5}|$$







share|cite|improve this answer














share|cite|improve this answer



share|cite|improve this answer








edited Nov 21 at 14:37

























answered Nov 21 at 14:23









Naweed G. Seldon

1,232419




1,232419












  • I think this is a silly question but how is $|sqrt2-i| = sqrt3$
    – Kaustuv Sawarn
    Nov 21 at 14:31












  • $|a+ib| = sqrt{a^2 + b^2}$, where $z = a+ib$. In this case, $a = sqrt2, b = -1$
    – Naweed G. Seldon
    Nov 21 at 14:36












  • haha, damn. I didn't even think like that! Thankyou very much!!
    – Kaustuv Sawarn
    Nov 21 at 15:03


















  • I think this is a silly question but how is $|sqrt2-i| = sqrt3$
    – Kaustuv Sawarn
    Nov 21 at 14:31












  • $|a+ib| = sqrt{a^2 + b^2}$, where $z = a+ib$. In this case, $a = sqrt2, b = -1$
    – Naweed G. Seldon
    Nov 21 at 14:36












  • haha, damn. I didn't even think like that! Thankyou very much!!
    – Kaustuv Sawarn
    Nov 21 at 15:03
















I think this is a silly question but how is $|sqrt2-i| = sqrt3$
– Kaustuv Sawarn
Nov 21 at 14:31






I think this is a silly question but how is $|sqrt2-i| = sqrt3$
– Kaustuv Sawarn
Nov 21 at 14:31














$|a+ib| = sqrt{a^2 + b^2}$, where $z = a+ib$. In this case, $a = sqrt2, b = -1$
– Naweed G. Seldon
Nov 21 at 14:36






$|a+ib| = sqrt{a^2 + b^2}$, where $z = a+ib$. In this case, $a = sqrt2, b = -1$
– Naweed G. Seldon
Nov 21 at 14:36














haha, damn. I didn't even think like that! Thankyou very much!!
– Kaustuv Sawarn
Nov 21 at 15:03




haha, damn. I didn't even think like that! Thankyou very much!!
– Kaustuv Sawarn
Nov 21 at 15:03


















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