Similar to how you can assign a value to a variable (see Section 3.3.2), use the := and => operators to define a function; both
| f(x):=x^2 |
and
| x^2=>f(x) |
give the name f to the function which takes a value and returns the square of the value. In either case, if you then enter:
| f(3) |
you will get:
|
You can define an anonymous function, namely a function without a name, with the -> operator; for example, the squaring function can be defined by
| x->x^2 |
use this form of the function to assign it a name; both
| f:=x->x^2 |
and
| x->x^2=>f |
are alternate ways to define f as the squaring function.
You can similarly define functions of more than one variable. For example you could enter
| hypot(a,b):=sqrt(a^2+b^2) |
or
| hypot:=(a,b)->sqrt(a^2+b^2) |
to define a function which takes the lengths of the two legs of a right triangle and returns the hypotenuse.