Sign of u and v in a complex variable

In summary, the equations for u and v can be rewritten as u=±(1/√2)*√(x+√(x^2+y^2 )) and v=±(1/√2)*√(-x+√(x^2+y^2 )). The signs for u and v can be chosen based on the real and imaginary parts of the complex function √(z).
  • #1
Fixxxer125
41
0

Homework Statement


if z=x+iy and sqrt(z) = u+iv

u=±(1/√2)*√(x+√(x^2+y^2 ))
v=±(1/√2)*√(-x+√(x^2+y^2 ))
How must the signs on these result be chosen?

2. The attempt at a solution
I wondered if it was something to do with ensuring √(z) was always positive, but then ruled this out as it is a complex function. I don't really know where to do with this one! Thanks for your help
 
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  • #2
Hi Fixxxer125! :smile:
Fixxxer125 said:
if z=x+iy and sqrt(z) = u+iv …

Do the obvious …

square the second equation: x + iy = z = (u + iv)2,

then equate real and imaginary parts (separately). :wink:
 
  • #3
Ah brilliant, thanks!
 

Related to Sign of u and v in a complex variable

What is the significance of the sign of u and v in a complex variable?

The sign of u and v in a complex variable represents the direction in which the complex number is pointing on the complex plane. It is also indicative of the quadrant in which the point is located.

How do we determine the sign of u and v in a complex variable?

The sign of u and v can be determined by looking at the real and imaginary components of a complex number. If the real component (u) is positive and the imaginary component (v) is positive, then the point is in the first quadrant and both u and v are positive. If u is negative and v is positive, the point is in the second quadrant and only v is positive. Similarly, if both u and v are negative, the point is in the third quadrant, and if u is positive and v is negative, the point is in the fourth quadrant.

Why is it important to consider the sign of u and v in a complex variable?

The sign of u and v is important because it helps us determine the direction of the complex number on the complex plane, which is crucial in many applications of complex numbers in mathematics and science. It also helps us identify the quadrant in which a point lies, which can aid in solving complex equations and understanding the behavior of functions in different regions of the complex plane.

Can the sign of u and v change in a complex variable?

Yes, the sign of u and v can change depending on the operation being performed on the complex number. For example, when multiplying two complex numbers, the sign of u and v may change based on the multiplication rules for real and imaginary components. It is important to pay attention to these changes when working with complex numbers.

Is there a relationship between the sign of u and v and the magnitude of a complex number?

No, the sign of u and v does not affect the magnitude of a complex number. The magnitude is determined solely by the distance of the point from the origin on the complex plane and is represented by the absolute value of the complex number.

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