The locus in the complex plane described by the equation Re 1 z = 1 4 ...
Let z=x+iy
1/z =1/x+iy
re(1/z)=x/
√x^2+y^2
and it is equal to 1/4
solving we get equation of a circle and u also can get radius
The locus in the complex plane described by the equation Re 1 z = 1 4 ...
Understanding the Equation
To solve the equation Re(1/z) = 1/4, we first need to express the complex number z in a suitable form. Let z = x + iy, where x and y are real numbers.
Finding Re(1/z)
1. Calculate 1/z:
- 1/z = 1/(x + iy) = (x - iy)/(x^2 + y^2)
- This gives us Re(1/z) = x/(x^2 + y^2).
2. Setting the equation:
- From the given equation, we have x/(x^2 + y^2) = 1/4.
Rearranging the Equation
- Rearranging gives us:
- 4x = x^2 + y^2
- This can be rearranged to:
- x^2 - 4x + y^2 = 0.
Completing the Square
- We complete the square for the x terms:
- (x^2 - 4x + 4) + y^2 = 4
- This simplifies to:
- (x - 2)^2 + y^2 = 4.
Identifying the Locus
- The equation (x - 2)^2 + y^2 = 4 represents a circle:
- Center: (2, 0)
- Radius: 2.
Conclusion
Thus, the locus described by the equation Re(1/z) = 1/4 is indeed a circle with a radius of 2. Therefore, the correct answer is option 'B'.