AP EAMCET202120 Aug 2021Morning ShiftMathematicsComplex NumberActual
The radius of the circle represented by ( 1 + i ) ( 1 + 3 i ) ( 1 + 7 i ) = x + i y is ( i = - 1 )
Options
- A1000
- B10 10
- C10000
- D100
Correct answer
B. 10 10
Step-by-step solution
The radius of the circle represented by ( 1 + i ) ( 1 + 3   i ) ( 1 + 7   i ) = x + i y (   1 +   3 i 2   +   4 i ) ( 1   +   7 i )   =   x   +   i y 1 +   3 i 2   +   4 i   +   7 i   +   21 i 3   +   28 i 2   =   - 30 - 10 i   =   x   +   i y x = - 30   ,   y = - 10 Radius of circle : ( x 2 + y 2 )   =   30 2 + 10 2   =   900 + 100   =   1000