Performing Sum to Product identity of trigonometric functions

[Thomas Klemm]

Meanwhile with my HP-48GX I can define:

Code:

DIR
  EXPR 'SIN(U+V)+SIN(U-V)'
  ∑→Π
    « {
        'SIN(&A)+SIN(&B)'
        '2*SIN((&A+&B)/2)*COS((&A-&B)/2)'
      } ↓MATCH
    »
END

And then run:

EXPR ∑→Π DROP COLCT COLCT

This results in:

'2*SIN(U)*COS(V)'