! GIBBS3 The square wave

!4/17/1996

!=============================================

! Number of terms in sum

LET N = 999

! Multiplier

LET M = .01

! Multiplier adjusts left and right of window

SET WINDOW -M*PI, M*PI, -2, 2

!=============================================

! Horizontal lines of grid

FOR J = -2 to 2 STEP 1

  PLOT -M*PI, J; M*PI, J

NEXT J

! Vertical lines of grid

FOR J = -1*M to 1*M STEP .25*M

  PLOT J*PI, -2; J*PI, 2

NEXT J

!=============================================

! Plot square wave

FOR X = -M*PI TO M*PI STEP 0.01*M

  LET Y = 0 

  FOR I = 1 TO N STEP 2

     LET Y = Y + (4/PI)*SIN(I*X)/I

  NEXT I

  PLOT X,Y

NEXT X

END