If |z−1|≤2 and ∣∣ωz−1−ω2∣∣=a (where ω is a cube root of unity), then complete set of values of a is
A
0≤a≤2
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B
12≤a≤√32
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C
√32−12≤a≤12+√32
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D
0≤a≤4
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Solution
The correct option is C0≤a≤4 |z−1|≤2 Since w is the cube root of unity. ∴w3=1&1+w+w2=0 |z−1|≤2∣∣wz−1−w2∣∣=a⇒|wz−w+2w|=a⇒|w||(z−1)+2|=a ⇒a≤|z−1|+2 ...{ ∵|z1+z2|≤|z2|+|z1| } ∵|z−1|≤2∴a≤4