1.

Suppose `A`is a complex number and `n in N ,`such that `A^n=(A+1)^n=1,`then the least value of `n`is`3`b. `6`c. `9`d. `12`A. 3B. 6C. 9D. 12

Answer» Correct Answer - B
Let `A=x+iy.`Given,
`|A|=1rArrx^(2)+y^(2)=1`
and `|A+1|=1rArr(x+1)^(2)+y^(2)=1`
`rArr x=-(1)/(2)andy=pm(sqrt3)/(2)`
`rArr A=omegaoromega^(2)`
`rArr (omega)^(n)=(1+omega)^(n)=(-omega^(2))^(2)`
Therefore, n must be even and divisible by 3.


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