Complex Numbers · NDA previous year questions

2009 13 questions

1. Q1012009 · 30 Aug 2009

   For the two equations $x^2+mx+1=0$ and $x^2+x+m=0$, what is/are the value/values of $m$ for which these equations have at least one common root ?

   1. A.$-2$ only
   2. B.1 only
   3. C.$-2$ and 1
   4. D.$-2$ and $-1$
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   Answer: C

2. Q1092009 · 30 Aug 2009

   If $z$ is a complex number such that $z+z^{-1}=1$, then what is the value of $z^{99}+z^{-99}$ ?

   1. A.1
   2. B.$-1$
   3. C.2
   4. D.$-2$
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   Answer: D