COMEDK2017MathematicsComplex Number
If z=r e^ i , then |e^ i z |=
Options
- A1
- Be^ 2 r
- Ce^ r
- De^ -r
Correct answer
D. e^ -r
Step-by-step solution
We have, aligned z &=r e^ i =r( +i ) i z &=i r( +i ) &=i r +i² r =-r +i r |e^ i z | &= |e^ (-r +i r ) | &= |e^ -r | |i r | &=e^ -r [ ²(r )+ ²(r ) ] &=e^ -r 1=e^ -r aligned