If | eeze^{e^z}eez | = 1 for a complex number z = x + iy, x, y ∈ R,then.which of thefollowing is true ?
Question
If | eez | = 1 for a complex number z = x + iy, x, y ∈ R,then.
which of thefollowing is true ?
A.
x=nπ for some integer n .
B.
y=(2n+1)2π for some integer n .
C.
y=nπ for some integer n .
D.
x=(2n+1)2π for some integer n.
Correct option is B
The given condition is eez=1, where z=x+iy.Step 1: Expand eezWe can write:eez=eex+iy=eexeiy.=eexcosy+exisiny=eexcosy⋅eexisinyThe modulus of eez is:eez=eexcosy⋅eexisiny=eexcosy⋅eexisinyTo satisfy the given condition:eez=eexcosy⋅eexisiny=1As, ∣eiθ∣=1,eexcosy=1is required.⟹cosy=0⟹y=2(2n+1)πHence, Option B is correct.