e^((11 pi)/(12) i) * e^(( pi) i)e11π12i⋅e(π)i
e^(i theta) = cos theta +i sin thetaeiθ=cosθ+isinθ
:. e^((11 pi)/(12) i) = (cos ((11 pi)/12)+ i sin ((11 pi)/12))
= - 0.9659 + 0.2588 i , II Quadrant
:. e^(( pi) i) = (cos (pi)+ i sin (pi))
= -1, II Quadrant.
:. e^((11 pi)/(12) i) * e^(( pi) i)
~~( - 0.9659 + 0.2588 i ) * ( -1 )
~~ 0.9659 - 0.2588 i
color(purple)(e^((11 pi)/(12) i) * e^(( pi) i) ~~ 0.9659 - 0.2588 i, IV Quadrant.
Verification :
=> e^i (((11pi)/12) + (pi))
=> e^i ((23pi)/12)
=> cos ((23pi)/12) + i sin ((23pi)/12)
=> 0.9659 - 0.2588i, IV Quadrant.