1. May 21, 2008

### m_s_a

suppose z=2+3i , w=1-5i
1)make Compare between z,w

2)find z!

3)IzI=sqart root (z^2)
or IzI=sqart root(zz')
IzI=sqart root (z^2)=sqart root(zz')

4) Compare between 1,i

5) i!=????

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. May 21, 2008

### Redbelly98

Staff Emeritus
Where is your attempt at a solution?

3. May 22, 2008

### Defennder

What does this mean?

4. May 22, 2008

### HallsofIvy

Staff Emeritus
1. What do you mean by "compare"? Find the difference? Absolute value of difference?

2. Is "!" supposed to be the factorial? It's only defined for positive integers, not complex numbers.

3. If, by ', you mean "complex conjugate", then $|z|= \sqrt{zz'}$ which is NOT the same as $\sqrt{z^2}$ unless z is real.

5. May 22, 2008

### m_s_a

6. May 22, 2008

### m_s_a

What is the meaning of the fifth question?

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7. May 23, 2008

### m_s_a

8. May 23, 2008

### Redbelly98

Staff Emeritus

5. Suppose f(z) = 3xy + i(x-y^2). Find lim{z -> 3+2i} of f(z), or explain carefully why it does not exist.

I am guessing that z=x+iy. I.e. z=3+2i means x=3 and y=2. However, this makes the question rather easy, just plugging in x=3 and y=2 into the given expression. If they mean something else I don't know what that is.

9. May 23, 2008

### Redbelly98

Staff Emeritus
I am unaware of any definition of "less than" or "greater than" concerning complex numbers.

10. May 24, 2008

### HallsofIvy

Staff Emeritus

Neither. The field of complex numbers is NOT an "ordered field".

11. May 26, 2008

### m_s_a

Defennder
HallsofIvy
Redbelly98
HallsofIvy

Thank you very much
Thank's alot