In polar coordinates, the point distance r from the origin and making an angle of θ to the x-axis has cartesian coordinates ( r cos θ, r sin θ ) where θ is measured in radians and –90° = –1.57080 radians = (4 cos( –90°), 4 sin( –90°) )
= (
0
,
–4
)
which, on the Argand diagram, is the complex number
0
–4
j
=
–4 j
AS Further Pure Mathematics(MEI Structured Mathematics FP1) Third Edition (2005) pages 54-66
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