split x and y coordinate values by comma
 e.g. : entry of "1,2" or "(1,2)" for point A and "3,4" for point B in dialog box . 
compute an y=a^{x} exponential function by selecting the "exponential type" checkbox instead of the one for the "linear type" (y=m*x+n) function
 or select a y=x^{2} parabel or sine function for drawing before finally pressing the "OK" button 
