# Help System (web edition)

```The following 'standard' functions are available (in editorial computing):
int,abs,ind,rnd,sqrt,log,exp,sin,cos,tan,arctan,arcsin,arccos.

Examples: int(3.7)=3 sqrt(1+24)=5
pi=3.1415926535898 sin(pi/4)=0.70710678118655
sqrt(2)/2=0.70710678118655
Also the following functions are available:
A modulo B: A=18 B=5 mod(A,B)=3
Greatest Common Divisor: GCD(144,270)=18
Binomial coefficient: C(10,5)=252
Factorial: fact(10)=3628800  Logarithm of factorial: lfact(1000)=5912.128178488
k-factorial: k_fact(10,4)=5040 (same as fact(10)/fact(10-4)=5040)
Logarithm of k-factorial: lk_fact(1000,500)=3300.797720028
Logarithm of gamma function: exp(lgamma(10))=362880
Riemann's zeta function: zeta(1.5)=2.6123753486855 (for real argument)
X(A,K) gives the value of the K'th `word' on the edit line A. (See XFUNC?)
round(x) gives the nearest integer: round(3.6)=4
round(x,d) rounds to d decimal places: round(3.456,2)=3.46 round(-171,-2)=-200
More functions on the next page!

max(a1,a2,...) gives the maximum of a1,a2,...
min(a1,a2,...) gives the minimum of a1,a2,...
maxn(a1,a2,...) gives the index of the maximal value.
minn(a1,a2,...) gives the index of the minimal value.
Example: a=1.9 max(sqrt(a),log(a+3),-tan(a/2))=1.5892352051166
maxn(sqrt(a),log(a+3),-tan(a/2))=2
days(day,month,year) gives number of days since day(1,1,2000)=0.