4.3BSD-Tahoe/usr/lib/learn/eqn/L8.1a

#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