The rational numbers are the set of all numbers that can be written as
fractions @var{p}/@var{q}, where @var{p} and @var{q} are integers.
All rational numbers are also real, but there are real numbers that
-are not rational, for example the square root of 2, and pi.
+are not rational, for example @m{\sqrt2, the square root of 2}, and
+@m{\pi,pi}.
Guile can represent both exact and inexact rational numbers, but it
can not represent irrational numbers. Exact rationals are represented
9.3-17.5i
@end lisp
+@cindex polar form
+@noindent
+Polar form can also be used, with an @samp{@@} between magnitude and
+angle,
+
+@lisp
+1@@3.141592 @result{} -1.0 (approx)
+-1@@1.57079 @result{} 0.0-1.0i (approx)
+@end lisp
+
Guile represents a complex number with a non-zero imaginary part as a
pair of inexact rationals, so the real and imaginary parts of a
complex number have the same properties of inexactness and limited
@deffn {Scheme Procedure} make-polar x y
@deffnx {C Function} scm_make_polar (x, y)
+@cindex polar form
Return the complex number @var{x} * e^(i * @var{y}).
@end deffn