MHB Complex Numbers VI: Finding Least Value of |z-2√2-4i|

Click For Summary
The discussion focuses on finding the least value of |z-2√2-4i| given the constraints |z-4i|≤√5 and π/4≤arg(z+4)≤π/2. Participants have sketched the loci on an Argand diagram and are exploring the intersection of these sets. The key challenge is determining the shortest distance from a point to a semi-disk, which involves identifying the complex number z_1 that minimizes this distance. There are also technical issues regarding the use of LaTeX for mathematical expressions. Ultimately, the goal is to find the exact form of z_1 and the corresponding least value.
Punch
Messages
44
Reaction score
0
Sketch on an Argand diagram the set of points satisfying both |z-4i|<=\sqrt{5} and \frac{\pi}{4}<=arg(z+4)<=\frac{\pi}{2}.

I have already sketched the 2 loci. The problem lies in the following part.

Hence find the least value of |z-2\sqrt{2}-4i|. Find, in exact form, the complex number z_1 represented by the point P that gives this least value.
 
Mathematics news on Phys.org
Punch said:
Hence find the least value of |z-2\sqrt{2}-4i|.
Over which set of z? The intersection defined in the first part? It seems that you need to find the shortest distance from a point to a semi-disk.

Why don't you wrap the [tex]...[/tex] tags around your formulas?
 
Evgeny.Makarov said:
Over which set of z? The intersection defined in the first part? It seems that you need to find the shortest distance from a point to a semi-disk.

Why don't you wrap the \(z_1\) tags around your formulas?

Yes, how do I then find the complex number z_1 in the following part?

I tried using the latex but they didnt seem to work
 
Punch said:
Yes, how do I then find the complex number z_1 in the following part?
See the following picture.

argand.png


Punch said:
I tried using the latex but they didnt seem to work
Type [tex]\frac{\pi}{4}\le\arg(z+4)\le\frac{\pi}{2}[/tex] to get \frac{\pi}{4}\le\arg(z+4)\le\frac{\pi}{2}.
 
Here is a little puzzle from the book 100 Geometric Games by Pierre Berloquin. The side of a small square is one meter long and the side of a larger square one and a half meters long. One vertex of the large square is at the center of the small square. The side of the large square cuts two sides of the small square into one- third parts and two-thirds parts. What is the area where the squares overlap?

Similar threads

  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 13 ·
Replies
13
Views
6K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 19 ·
Replies
19
Views
3K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 5 ·
Replies
5
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K