#once #create message .ND .LP The next neqn operation is called "sqrt" - it makes square root signs over things, like this: .EQ sqrt a+b .EN (They don't look very good on a terminal, unfortunately.) This one is very easy - to print the line above, you say .EQ sqrt a+b .EN The "sqrt" operates on the first thing it finds so if you want something more complicated, like .EQ sqrt {pi +1} .EN you have to use braces to enclose the entire thing. This one was printed with .EQ sqrt {pi +1} .EN And that's all there is to sqrt. Modify "Example" so it looks like this, then type "ready". .pl 1 #once #create Ref .LP .EQ f(x) ~=~ sqrt {ax sup 2 +bx+c} .EN .pl 1 #once #create Example .LP .EQ f(x).... .EN .pl 1 # #once neqn Ref | nroff >X1 & #once neqn message Ref | nroff -T$term %s/tinyms - #user neqn Example | nroff >X2 #cmp X1 X2 #log #next 8.1b 10