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If (1−i)n=2n ......(i)
We know that if two complex numbers are equal, their moduli must also be equal, therefore from (i), we have
|(1−i)n|=|2n|⇒|1−i|n=|2|n, (∵ 2n>0)
⇒ [√12+(−1)2]=2n⇒(√2)n=2n
2n/2=2n⇒n2=n⇒ n=0
Trick : By inspection, (1−i)0=20⇒1=1