Given,
z 0 = 1 + 3 i 2 , z 1 = ( 1 + i ) {z}_{0} = \dfrac{1 + 3i}{2}, {z}_{1} = \left(1 + i\right) z 0 = 2 1 + 3 i , z 1 = ( 1 + i )
So, \left|{z}_{1} - {z}_{0}\right| = \sqrt{{\left(1 - \dfrac{1}{2}\right)}^{2} + {\left(1 - \dfrac{3}{2}\right)}^{2}} = \sqrt{\dfrac{1}{4} + \dfrac{1}{4}} = \dfrac{1}{\sqrt{2}}< / p > < p > A n d </p><p>And < / p >< p > A n d {z}_{2}b e o u t s i d e c i r c l e , ∣ z 1 − z 0 ∣ ∣ z 2 − z 0 ∣ = 1 be outside circle, \left|{z}_{1} - {z}_{0}\right|\left|{z}_{2} - {z}_{0}\right| = 1 b eo u t s i d ec i rc l e , ∣ z 1 − z 0 ∣ ∣ z 2 − z 0 ∣ = 1
⇒ 1 2 ∣ z 2 − z 0 ∣ = 1 ⇒ \dfrac{1}{\sqrt{2}}\left|{z}_{2} - {z}_{0}\right| = 1 ⇒ 2 1 ∣ z 2 − z 0 ∣ = 1
⇒ ∣ z 2 − z 0 ∣ = 2 ⇒ \left|{z}_{2} - {z}_{0}\right| = \sqrt{2} ⇒ ∣ z 2 − z 0 ∣ = 2
Now given, z 0 , z 1 and z 2 {z}_{0}, {z}_{1} \text{ and } {z}_{2} z 0 , z 1 and z 2 are collinear,
So, by concept of rotation we get,
z 2 − z 0 z 1 − z 0 = ∣ z 2 − z 0 ∣ ∣ z 1 − z 0 ∣ e i 0 \dfrac{{z}_{2} - {z}_{0}}{{z}_{1} - {z}_{0}} = \dfrac{\left|{z}_{2} - {z}_{0}\right|}{\left|{z}_{1} - {z}_{0}\right|}{e}^{i0} z 1 − z 0 z 2 − z 0 = ∣ z 1 − z 0 ∣ ∣ z 2 − z 0 ∣ e i 0
⇒ z 2 − z 0 z 1 − z 0 = ∣ z 2 − z 0 ∣ ∣ z 1 − z 0 ∣ ( ± 1 ) ⇒ \dfrac{{z}_{2} - {z}_{0}}{{z}_{1} - {z}_{0}} = \dfrac{\left|{z}_{2} - {z}_{0}\right|}{\left|{z}_{1} - {z}_{0}\right|}\left(\pm 1\right) ⇒ z 1 − z 0 z 2 − z 0 = ∣ z 1 − z 0 ∣ ∣ z 2 − z 0 ∣ ( ± 1 )
⇒ z 2 − z 0 z 1 − z 0 = ± 2 ⇒ \dfrac{{z}_{2} - {z}_{0}}{{z}_{1} - {z}_{0}} = \pm 2 ⇒ z 1 − z 0 z 2 − z 0 = ± 2
⇒ z 2 = z 0 ± 2 ( z 1 − z 0 ) ⇒ {z}_{2} = {z}_{0} \pm 2\left({z}_{1} - {z}_{0}\right) ⇒ z 2 = z 0 ± 2 ( z 1 − z 0 )
So, z 2 = 2 z 1 − z 0 = 3 2 + 1 2 i ⇒ ∣ z 2 ∣ 2 = 5 2 {z}_{2} = 2{z}_{1} - {z}_{0} = \dfrac{3}{2} + \dfrac{1}{2}i ⇒ {\left|{z}_{2}\right|}^{2} = \dfrac{5}{2} z 2 = 2 z 1 − z 0 = 2 3 + 2 1 i ⇒ ∣ z 2 ∣ 2 = 2 5
Or z 2 = 3 z 0 − 2 z 1 = − 1 2 + 5 2 i ⇒ ∣ z 2 ∣ 2 = 13 2 {z}_{2} = 3{z}_{0} - 2{z}_{1} = \dfrac{- 1}{2} + \dfrac{5}{2}i ⇒ {\left|{z}_{2}\right|}^{2} = \dfrac{13}{2} z 2 = 3 z 0 − 2 z 1 = 2 − 1 + 2 5 i ⇒ ∣ z 2 ∣ 2 = 2 13
Hence, the smaller value will be, ∣ z 2 ∣ 2 = 5 2 {\left|{z}_{2}\right|}^{2} = \dfrac{5}{2} ∣ z 2 ∣ 2 = 2 5