SUBROUTINE Euler(y,x,delta_x)
* variables slope and change introduced for sake of clarity only
IMPLICIT NONE
REAL*8 change, slope, y, x, delta_x
slope = 2*x ! slope at beginning of interval
change = slope*delta_x ! estimate of change during interval
y = y + change ! new value of y
x = x + delta_x ! value of x at end of interval
END