- Home
- Standard 11
- Mathematics
4-1.Complex numbers
normal
If $z_1$ is a point on $z\bar{z} = 1$ and $z_2$ is another point on $(4 -3i)z + (4 + 3i)z -15 = 0$, then $|z_1 -z_2|_{min}$ is (where $ i = \sqrt { - 1}$ )
A
$\frac{1}{2}$
B
$2$
C
$\frac{3}{2}$
D
$4$
Solution
$z \bar{z}=1 \Rightarrow x^{2}+y^{2}=1$
$(4-3 i) z+(4+3 i) \bar{z}-15=0$
$\Rightarrow 8 x+6 y-15=0$
Minimum distance of line from circle
$=\frac{3}{2}-1=\frac{1}{2}$
Standard 11
Mathematics