2DVEC+ hp32sII
A small program to add two planar vectors given their magnitudes and
polar angles (from some line). The answer gives the magnitude and
angle of the sum.

Input in the stack
  T: angle of first vector
  Z: magnitude of first vector
  Y: angle of second vector
  X: magnitude of second vector

Output in the stack
  Y: angle of sum
  X: magnitude of sum

This program does not use any variables. It only manipulates the stack.

Memory requirements:
  Total: 12 bytes. Program: 12 bytes. Variables: 0.
  Left free: 372 bytes. No Flags used.
  CHKSUM=7A0B   012.0

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A01 LBL A
A02 theta,r->y,x
A03 Rdown
A04 Rdown
A05 theta,r->y,x
A06 CMPLX+
A07 y,x->theta,r
A08 RTN