To draw a square root, use
sqrt:
sqrt a+b + 1 over sqrt {ax sup 2 +bx+c}
is
Warning _ square roots of tall quantities look lousy,
because a root-sign
big enough to cover the quantity is
too dark and heavy:
sqrt {a sup 2 over b sub 2}
is
Big square roots are generally better written as something to the power ½:
which is
(a sup 2 /b sub 2 ) sup half