FUNCTION FTBM(CONS)
      IMPLICIT REAL*8 (A-H,O-Z)
      DIMENSION CONS(2)
      COMPLEX*16 E,ARG,EQN
      DATA R,V0/10d0,1000d0/
      E=CMPLX(ABS(CONS(1)),CONS(2))
      ARG=SQRT(2*(E+V0))
      EQN=ARG*COS(ARG*R)/SIN(ARG*R)-(0,1)*SQRT(2*E)
      FTBM=ABS(EQN)
      RETURN
      END