( 321 ) 



. • • (/) 



f, -f/r f J '_ 4w'g l e 1 



{n-iy \ "(n-ï, 

 and so a parabola. We see from of (y') thai this parabola touches 

 the f i axis and the e, axis in the points of intersection in which the 



straight line— ^y= l intersects the axes. The equation of this 



(n-i)z 



Fig. 36. 



parabola may he written in the form 1(1 "~ * i n —iy "*" 



from which apprai-s that the direction of the axis or of the diameters 



of this parabola is given by : 



