99 Percentile Qs Bank for JEE MainMathematicsComplex Number
. If , are the roots of the equation x^2-2 x+4=0 , then ^n+ ^n= ( n 3 ) for any n N
Options
- A2^n
- B2^ n+1
- C2^ n-1
- D2^ n-2
Correct answer
B. 2^ n+1
Step-by-step solution
Given quadratic equation x^2-2 x+4=0 having roots and . So, , = 2 4-16 2 = 2 2 3 i 2 =1 3 i gathered =2 ( 3 +i 3 ) and 2 ( (- 3 )+i (- 3 ) ) ^ n+ + ^ n t =2^ n t [ ( 3 +i 3 )^n . .+ ( (- 3 )+i (- 3 ) )^n ] =2^ n t [2 n 3 ]=2^ n+1 ( n 3 ) gathered