Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
AP EAMCET20225 Jul 2022Evening ShiftMathematicsComplex NumberActual

_ k=1 ^6 ( 2 k 7 )-i ( 2 k 7 )=

Options

  1. A1
  2. B-i
  3. Ci
  4. D-1

Correct answer

C. i

Step-by-step solution

_ k=1 ^6-i [ 2 k 7 +i 2 k 7 ] +i =e^ i (-i) _ k=1 ^6 e^ i 2 k 7 =(-i) [e^ i 2 7 +e^ i 4 7 +e^ i 6 7 + +e^ i 12 7 ]=-i e^ i 2 7 (1- (e^ i 2 7 )^6 ) 1-e^ i 2 7 (sum of GP) =-i [ e^ i 2 7 -e^ i 14 7 1-e^ i 2 7 ]=-i [ e^ i 2 7 -e^ i 2 1-e^ i 2 7 ] e^ i 2 = 2 +i 2 =1 .=-i [ e^ i 2 7 -1 1-e^ i 2 7 ]=-i(-1)=i

Practice Complex Number on Quantrex Academy →

More from Complex Number

If z and are two non-zero complex numbers such that |z |=1 and Arg z- Arg = 2 then z = 2025Let z satisfy |z|=1, z=1- z and Im (z)>0 Statement-I : z is a real number Statement-II : Principal argument of z is 3 . Then 2025If ₁ and ₂ are two non-zero complex numbers and a , b are non zero real numbers such that | a ₁+ b ₂ |= | a ₁- b ₂ | , then ₁ ₂ is 2025If a complex number z=x+i y represents a point P on the Argand plane and Arg ( z-3+2 i z+2-3 i )= 4 , then the locus of P is a 2025By taking a i b =x i y, x>0 , if we get 21+12 2 i 21-12 2 i =a+i b , then b a = 2025Two values of (-8-8 3 i)^ 1 / 4 are 2025If x=3-2 3 i , then x^4-12 x^3+54 x^2-108 x-54= 2025z ₁, z ₂, z ₃ represent the vertices A , B , C of a triangle ABC respectively in the Argand plane. If |z₁-z₂ |= 25-12 3 , | z₁-z₃ z₂-z₃ |= 3 4 and ACB =30^ , then the area (in sq. 2025 Full Complex Number list All AP EAMCET PYQs