.G1 frame ht 2.5 wid 2.5 coord x 0,1 y 0,1 label bot "Direction field is $y sup prime = x sup 2 / y$" label left "$y = sqrt {(2x sup 3 +1)/3}$" right .3 ticks left in 0 at 0,1 ticks bot in 0 at 0,1 len = .04 for tx from .01 to .91 by .1 do { for ty from .01 to .91 by .1 do { deriv = tx*tx/ty scale = len/sqrt(1+deriv*deriv) line from tx,ty to tx+scale,ty+scale*deriv } } draw solid for tx = 0 to 1 by .05 do { next at tx, sqrt((2*tx*tx*tx+1)/3) } .G2