Question 1090709
<pre><font size = 5><b>
The complex number -6i equals 0-6i and is equal to the vector 
whose tail is at the origin and whose tip is at the point (0,-6).
It is 6 units long, so its mudulus r is 6 and its argument <font face="symbol">q</font> is 270°,
indicated by the counter clockwise arc from the right side of the
x-axis to the vector which represents the complex number:

{{{drawing(400,400,-6,6,-6,6,red(arc(0,0,1,-1,0,270),
locate(-1,1,theta="270°")),

triangle(-15,0,15,0,14,0), line(0,0,0,-2),line(.2,-1.7,0,-2), line(-.2,-1.7,0,-2),
triangle(0,-15,0,15,0,14),locate(0,-2,"(0,-6)") )}}}

So the complex number = -6i = 6(cos270° + i&#8729;sin270°) 

Edwin</pre></font></b>