%%%%
 tex{\input pictex}
 pictex{$$\beginpicture}
 paper{units(2cm,2cm),xrange(-2,2),yrange(0,2)}
 pictex{\axis left shiftedto y=0 ticks numbered }
 pictex{ from 1 to 2 by 1 /}
 pictex{\axis bottom  shiftedto x=0 ticks numbered from -2 to 0 by 1}
 pictex{ from 1 to 2 by 1 /}
 point(A){0,0}
 point(B){A,polar (1,0 deg)}
 point(C){A,polar (1,0 deg)}
 %point(z2){A,polar (1,45 deg)}
 %point(z1){A,polar (1,30 deg)}
 %point(z3){A,polar (1,75 deg) }
 point(z4){A,polar (1.7, 135 deg)}
 drawPoints(z4)
 drawLine(A z4)
 drawAngleArrow{angle(B A z4),radius(0.4), internal, anticlockwise}
 \pictex{\setdashes}
 drawPerpendicular(z4 , A B)
 \pictex{\setsolid}
 text($\theta$){A, polar (0.5,70deg)}[bl]
 text($z = x + i y = |z| (\cos \theta + i \sin \theta)$){z4, shift (0,.1)}[b]
 text($y$){z4, shift(-.2,-.5)}[l]
 text($x$){A, shift (-.6, .1)}[b]
 %text($z_1= \mathop{\rm cis}30^{\circ}$) {z1}[tl]
 %text($z_2= \mathop{\rm cis}45^{\circ}$) {z2}[bl]
 %text($z_3 = z_1 \cdot z_2 = = \mathop{\rm cis}75^{\circ}$) {z3, shift(.1,.1)}[bl]
 %drawLine(A z1)
 %drawLine(A z2)
 %drawLine(A z3)
 %DrawAngleArrow{angle(B A z1 ), radius(0.5), internal ,anticlockwise}
 %DrawAngleArrow{angle(B A z2 ), radius(0.65), internal ,anticlockwise}
 pictex{\endpicture$$}
 %%%tex{\bye}
