01Medium53×since 2002Q3220If a > 0 and z = (1+i)2a−i{{{{\left( {1 + i} \right)}^2}} \over {a - i}}a−i(1+i)2, has magnitude 25\sqrt {{2 \over 5}}52, then z‾\overline zz is equal to :A−15+35i- {1 \over 5} + {3 \over 5}i−51+53iB−15−35i- {1 \over 5} - {3 \over 5}i−51−53iC15−35i{1 \over 5} - {3 \over 5}i51−53iD−35−15i- {3 \over 5} - {1 \over 5}i−53−51iCheck answerSkip
02Medium53×since 2002Q3221If the equation, x² + bx + 45 = 0 (b ∈\in∈ R) has conjugate complex roots and they satisfy |z +1| = 210\sqrt {10}10 , then :Ab² – b = 42Bb² + b = 12Cb² + b = 72Db² – b = 30Check answerSkip
03Easy53×since 2002Q3222If α\alphaα, β\betaβ ∈\in∈ R are such that 1 −-− 2i (here i² = −-−1) is a root of z² + α\alphaαz + β\betaβ = 0, then (α\alphaα −-− β\betaβ) is equal to :A−-−7B7C3D−-−3Check answerSkip
04Medium53×since 2002Q3223Let n denote the number of solutions of the equation z² + 3z‾\overline zz = 0, where z is a complex number. Then the value of ∑k=0∞1nk\sum\limits_{k = 0}^\infty {{1 \over {{n^k}}}}k=0∑∞nk1 is equal to :A1B43{4 \over 3}34C32{3 \over 2}23D2Check answerSkip
05Medium53×since 2002Q3224The area of the polygon, whose vertices are the non-real roots of the equation z‾=iz2\overline z = i{z^2}z=iz2 is :A334{{3\sqrt 3 } \over 4}433B332{{3\sqrt 3 } \over 2}233C32{3 \over 2}23D34{3 \over 4}43Check answerSkip
06Medium53×since 2002Q3225The real part of the complex number (1+2i)8 . (1−2i)2(3+2i) . (4−6i)‾{{{{(1 + 2i)}^8}\,.\,{{(1 - 2i)}^2}} \over {(3 + 2i)\,.\,\overline {(4 - 6i)} }}(3+2i).(4−6i)(1+2i)8.(1−2i)2 is equal to :A50013{{500} \over {13}}13500B11013{{110} \over {13}}13110C556{{55} \over {6}}655D55013{{550} \over {13}}13550Check answerSkip
07Easy53×since 2002Q3226If z=2+3iz=2+3 iz=2+3i, then z5+(zˉ)5z^{5}+(\bar{z})^{5}z5+(zˉ)5 is equal to :A244B224C245D265Check answerSkip
08Medium53×since 2002Q3227If the set {Re(z−zˉ+zzˉ2−3z+5zˉ):z∈C,Re(z)=3}\left\{\operatorname{Re}\left(\frac{z-\bar{z}+z \bar{z}}{2-3 z+5 \bar{z}}\right): z \in \mathbb{C}, \operatorname{Re}(z)=3\right\}{Re(2−3z+5zˉz−zˉ+zzˉ):z∈C,Re(z)=3} is equal to the interval (α,β](\alpha, \beta](α,β], then 24(β−α)24(\beta-\alpha)24(β−α) is equal to :A36B27C42D30Check answerSkip
09Medium53×since 2002Q3228Let S={z∈C:zˉ=i(z2+Re(zˉ))}S=\left\{z \in \mathbb{C}: \bar{z}=i\left(z^{2}+\operatorname{Re}(\bar{z})\right)\right\}S={z∈C:zˉ=i(z2+Re(zˉ))}. Then \sum_\limits{z \in \mathrm{S}}|z|^{2} is equal to :A72\frac{7}{2}27B4C3D52\frac{5}{2}25Check answerSkip
10Hard53×since 2002Q3229For a∈Ca \in \mathbb{C}a∈C, let A={z∈C:Re(a+zˉ)>Im(aˉ+z)}\mathrm{A}=\{z \in \mathbb{C}: \operatorname{Re}(a+\bar{z}) > \operatorname{Im}(\bar{a}+z)\}A={z∈C:Re(a+zˉ)>Im(aˉ+z)} and B={z∈C:Re(a+zˉ)<Im(aˉ+z)}\mathrm{B}=\{z \in \mathbb{C}: \operatorname{Re}(a+\bar{z})<\operatorname{Im}(\bar{a}+z)\}B={z∈C:Re(a+zˉ)<Im(aˉ+z)}. Then among the two statements : (S1): If Re(a),Im(a)>0\operatorname{Re}(a), \operatorname{Im}(a) > 0Re(a),Im(a)>0, then the set A contains all the real numbers (S2) : If Re(a),Im(a)<0\operatorname{Re}(a), \operatorname{Im}(a) < 0Re(a),Im(a)<0, then the set B contains all the real numbers,Aboth are falseBonly (S1) is trueConly (S2) is trueDboth are trueCheck answerSkip