JEE Main On 08 April 2018 Question 3

Question: If $ \alpha ,\beta \in C $ are the distinct roots, of the equation $ x^{2}-x+1=0, $ then $ {{\alpha }^{101}}+{{\beta }^{107}} $ is equal to: [JEE Main Online 08-04-2018]

Options:

A) 1

B) 2

C) -1

D) 0

Show Answer

Answer:

Correct Answer: A

Solution:

  • 1 Roots of $ x^{2}-x+1=0 $ are $ (-\omega ,-{{\omega }^{2}}) $
    $ \Rightarrow \alpha =-\omega ,\beta =-{{\omega }^{2}} $
    $ \Rightarrow {{\alpha }^{101}}+{{\beta }^{107}} $
    $ \Rightarrow {{(-\omega )}^{101}}+{{(-{{\omega }^{2}})}^{107}} $
    $ \Rightarrow -{{\omega }^{2}}-\omega =1 $