Home
Class 12
MATHS
If Re (lambda Z + (2)/(Z)) is zero and R...

If Re `(lambda Z + (2)/(Z))` is zero and Re(z) `!= 0` and |Z| = 2. Then `lambda` can be

A

2

B

`-2`

C

`(1)/(2)`

D

`-(1)/(2)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the value of \(\lambda\) given that the real part of the expression \(\lambda z + \frac{2}{z}\) is zero, where \(z\) is a complex number with \(|z| = 2\) and \(\text{Re}(z) \neq 0\). ### Step-by-Step Solution 1. **Express \(z\) in terms of its components:** Let \(z = x + iy\), where \(x\) and \(y\) are real numbers. 2. **Calculate \(|z|\):** Given \(|z| = 2\), we have: \[ |z| = \sqrt{x^2 + y^2} = 2 \implies x^2 + y^2 = 4. \] 3. **Substitute \(z\) into the expression:** We need to evaluate the expression \(\lambda z + \frac{2}{z}\): \[ \lambda z + \frac{2}{z} = \lambda(x + iy) + \frac{2}{x + iy}. \] 4. **Rationalize \(\frac{2}{z}\):** To simplify \(\frac{2}{z}\), we multiply by the conjugate: \[ \frac{2}{z} = \frac{2}{x + iy} \cdot \frac{x - iy}{x - iy} = \frac{2(x - iy)}{x^2 + y^2} = \frac{2(x - iy)}{4} = \frac{x}{2} - \frac{iy}{2}. \] 5. **Combine the terms:** Now substitute back into the expression: \[ \lambda(x + iy) + \left(\frac{x}{2} - \frac{iy}{2}\right) = \lambda x + \frac{x}{2} + i(\lambda y - \frac{y}{2}). \] 6. **Separate the real and imaginary parts:** The real part is: \[ \text{Re}(\lambda z + \frac{2}{z}) = \lambda x + \frac{x}{2}. \] The imaginary part is: \[ \text{Im}(\lambda z + \frac{2}{z}) = \lambda y - \frac{y}{2}. \] 7. **Set the real part to zero:** According to the problem, we set the real part to zero: \[ \lambda x + \frac{x}{2} = 0. \] 8. **Factor out \(x\):** Since \(\text{Re}(z) \neq 0\), we can divide by \(x\): \[ \lambda + \frac{1}{2} = 0 \implies \lambda = -\frac{1}{2}. \] 9. **Conclusion:** The value of \(\lambda\) is: \[ \lambda = -\frac{1}{2}. \]

To solve the problem, we need to find the value of \(\lambda\) given that the real part of the expression \(\lambda z + \frac{2}{z}\) is zero, where \(z\) is a complex number with \(|z| = 2\) and \(\text{Re}(z) \neq 0\). ### Step-by-Step Solution 1. **Express \(z\) in terms of its components:** Let \(z = x + iy\), where \(x\) and \(y\) are real numbers. 2. **Calculate \(|z|\):** ...
Promotional Banner

Topper's Solved these Questions

  • MOCK TEST 12

    VMC MODULES ENGLISH|Exercise MATHEMATICS (SECTION 2)|5 Videos
  • MOCK TEST 11

    VMC MODULES ENGLISH|Exercise MATHEMATICS (Section-2)|5 Videos
  • MOCK TEST 13

    VMC MODULES ENGLISH|Exercise MATHEMATICS( SECTION-2)|5 Videos

Similar Questions

Explore conceptually related problems

If (1+i)^2 /(3 - i) , then Re(z) =

z is a complex number such that |Re(z)| + |Im (z)| = 4 then |z| can't be

z is a complex number such that |Re(z)| + |Im (z)| = 4 then |z| can't be

If |z|=k and omega=(z-k)/(z+k) , then Re (omega) =

If Re ((z + 2i)/(z+4))= 0 then z lies on a circle with centre :

If line (x-2)/(3)=(y-4)/(4)=(z+2)/(1) is paralle to planes mux+3y-2z+d=0 and x-2lambda y+z=0 then value of lambda and mu are

For any two complex numbers z_(1) "and" z_(2) , abs(z_(1)-z_(2)) ge {{:(abs(z_(1))-abs(z_(2))),(abs(z_(2))-abs(z_(1))):} and equality holds iff origin z_(1) " and " z_(2) are collinear and z_(1),z_(2) lie on the same side of the origin . If abs(z-(2)/(z))=4 and sum of greatest and least values of abs(z) is lambda , then lambda^(2) , is

If |Z-2|=2|Z-1| , then the value of (Re(Z))/(|Z|^(2)) is (where Z is a complex number and Re(Z) represents the real part of Z)

Number of solutions of Re(z^(2))=0 and |Z|=a sqrt(2) , where z is a complex number and a gt 0 , is

If z_(1) and z_(2) satisfy the equation |z-2|=|"Re"(z)| and arg (z1-z2)=pi/3, then Im (z1+z2) =k/sqrt 3 where k is