JEE Main2013MathematicsComplex NumberActual
Let z satisfy |z|=1 and z=1- z . Statement 1: z is a real number. Statement 2 : Principal argument of z is 3
Options
- AStatement 1 is true Statement 2 is true; Statement 2 is a correct explanation for Statement 1 .
- BStatement 1 is false; Statement 2 is true
- CStatement 1 is true, Statement 2 is false.
- DStatement 1 is true; Statement 2 is true; Statement 2 is not a correct explanation for Statement 1 .
Correct answer
B. Statement 1 is false; Statement 2 is true
Step-by-step solution
Let z=x+i y, z =x-i y aligned & Now, z=1- z & x+i y=1-(x-i y) & 2 x=1 x= 1 2 & Now, |z|=1 x^2+y^2=1 y^2=1-x^2 & y= 3 2 aligned Now, = y x ( is the argument ) = 3 2 1 2 (+ve since only principal argument) gathered = 3 = ⁻¹ 3 = 3 gathered Hence, z is not a real number So, statement-1 is false and 2 is true.