small doc edits

svn: r6586

collects/scribble/scribble.css

@@ -5,6 +5,7 @@
                max-width: 35em;
                margin-left: auto;
                margin-right: auto;
+               padding-left: 0.5em;
                font-family: Times;
                }
 

collects/scribblings/guide/numbers.scrbl

@@ -76,9 +76,10 @@ types of numbers.
 (inexact->exact 0.1)
 ]
 
-Inexact results are also produced by trancendental procedures such as
-@scheme[sin] and @scheme[cos], in part because Scheme can only
-represent rational numbers.
+Inexact results are also produced by procedures such as @scheme[sqrt],
+@scheme[log], and @scheme[sin] when an exact result would require
+representing real numbers that are not rational. Scheme can represent
+only rational numbers and complex numbers with rational parts.
 
 @examples[
 (code:line (sin 0)   (code:comment #, @t{rational...}))
@@ -133,4 +134,16 @@ compares numbers considering both exactness and numerical equality.
 (eqv? 1 1.0)
 ]
 
+Beware of comparisons involving inexact numbers, which by their nature
+can have surprising behavior. Even apparently simple inexact numbers
+may not mean what you think they mean; for example, while a base-2
+IEEE floating-point number can represent @scheme[1/2] exactly, it
+can only approximate @scheme[1/10]:
+
+@examples[
+(= 1/2 0.5)
+(= 1/10 0.1)
+(inexact->exact 0.1)
+]
+
 @refdetails["mz:numbers"]{numbers and number procedures}

collects/scribblings/guide/pairs.scrbl

@@ -11,7 +11,7 @@
 A @defterm{pair} joins two arbitrary values. The @scheme[cons]
 procedure constructs pairs, and the @scheme[car] and @scheme[cdr]
 procedures extract the first and second elements of the pair,
-respectively. The @scheme[pair?] predicate recogizes pairs.
+respectively. The @scheme[pair?] predicate recognizes pairs.
 
 Some pairs print by wrapping parentheses around the printed forms of
 the two pair elements, putting a @litchar{.} between them.

collects/scribblings/reference/numbers.scrbl

@@ -61,7 +61,7 @@ infinity, or @scheme[+nan.0] if no such limit exists.
 A @pidefterm{fixnum} is an exact integer whose two's complement
 representation fit into 31 bits on a 32-bit platform or 63 bits on a
 64-bit platform. Two fixnums that are @scheme[=] are also the same
-according to @scheme[eq?]. Otherwise, the result of @scheme{eq?}
+according to @scheme[eq?]. Otherwise, the result of @scheme[eq?]
 applied to two numbers is undefined.
 
 Two numbers are @scheme[eqv?] when they are both inexact or both