User's Manual

Functions and commands 403
nDeriv Given an expression, a variable of differentiation, and a real
number h, returns an approximate value of the derivative of
the expression, using f’(x)=(f(x+h)–f(x+h))/(2*h).
Without a third argument, the value of h is set to 0.001; with
a real as third argument, it is the value of h. With a variable
as the third argument, returns the expression above with that
variable in place of h.
nDeriv(Expr,Var, Real) or
nDeriv(Expr, Var1, Var2)
Example:
nDeriv(f(x),x,h) returns (f(x+h)-(f(x-h)))*0.5/h
NEG Unary minus. Enters the negative sign.
normal Returns the expanded irreducible form of an expression.
normal(Expr)
Example:
normal(2*x*2) gives 4*x
normalize Given a vector, returns it divided by its l
2
norm (where the l
2
norm is the square root of the sum of the squares of the
vector’s coordinates).
Given a complex number, returns it divided by its modulus.
normalize(Vector) or normalize(Complex)
Example:
normalize(3+4*i) gives (3+4*i)/5
NOT Returns the logical inverse of a Boolean expression.
not(Expr)
odd Returns 1 if a given integer is odd, and returns 0 otherwise.
odd(Integer)
Example:
odd(6) gives 0
OR Logical Or. Returns 1 if either or both sides evaluates to true
and 0 otherwise.
Expr1 OR Expr2
Example:
3 +1==4 OR 8 < 5 returns 1