Mathematic Functions and Operators

The following list includes both WebAssign-specific and commonly used Perl functions and operators that are available when creating questions.

Numerical Operators

Operation	Usage	Notes
Test Numerical Equality	`==`	Returns true (1) or false (0). Use `eq` to compare strings.
Test Numerical Inequalities ( ≠ > < ≥ ≤ )	`!= > < >= <=`	Returns true (1) or false (0). To compare strings, use `ne`, `gt`, `lt`, `ge`, `le`.
Addition, Subtraction, Multiplication, Division	`+ - * /`
Exponentiation	`**`
Order of Operations	`()`	Do not use `[]` or `{}`.

Mathematic Functions

Operation	Usage	Notes
Absolute value	`abs(n)`
Average (mean)	`avg(n1,n2,...)`	Returns the mean of the values. Argument can be a list or an array. Example: `$mean = avg(@array_x) $mean2 = avg(3,4,5)`
Greatest Common Divisor	`gcd(n1,n2,...)`	Argument can be a list or an array.
Least Common Multiple	`lcm(n1,n2,...)`	Argument can be a list or an array.
Maximum value	`max(n1,n2,...)`	Returns the greatest value. Argument can be a list or an array.
Minimum value	`min(n1,n2,...)`	Returns the least value. Argument can be a list or an array.
Pearson's correlation coefficient	`corr(@array_x, @array_y)`	Returns the correlation between the values in two arrays. The arrays should be the same size.
Sample standard deviation	`stdev(n1,n2, ...)`	Returns the sample standard deviation of the values. Argument can be a list or an array. Example: `$s = stdev(@array_x)`
Slope of a bivariate linear regression	`linregb(@array_x, @array_y)`	Returns the slope of a linear regression using the values in two arrays. The arrays should be the same size. Example: `$slope = linregb(@array_x,@array_y)`
Square root	`sqrt(n)`	`n` ≥ 0
Sum of array or list	`sum(n1,n2,...)`	Returns the sum of the array or list. Argument can be a list or an array. Example: `$total = sum(23,45,56,78) $total2 = sum(@array_x)`
Sum of products	`ssxy(@array_x, @array_y)`	Returns the sum of the products of the deviations of the values of two arrays. The arrays should be the same size.
Sum of squared deviations	`ssx(n1,n2, ...)`	Returns the sum of squared deviations about the mean of the values. Argument can be a list or an array. Example: `$ssofx = ssx(@array_x)`
Y intercept of a bivariate linear regression	`linrega(@array_x, @array_y)`	Returns the y intercept of a linear regression using the values in two arrays. The arrays should be the same size. Example: `$intercept = linrega(@array_x,@array_y)`

Trigonometric Functions

Operation	Usage	Notes
Trigonometric Functions	`sin(n) sec(n) cos(n) csc(n) tan(n) cot(n)`	The value of `n` must be in radians. Non-canonical values of `n` might return approximate values.
Inverse Trigononometric Functions	`asin(n) asec(n) acos(n) acsc(n) atan(n) acot(n)`	Returns principal values in radians.
Arctangent of `y`/`x`	`atan2(y,x)`	Returns radians from −π through π.
pi (π)	`pi`
Degrees to radians	`rad(n)`	Converts degrees to radians.
Radians to degrees	`deg(n)`	Converts radians to degrees.
Get canonical angle in degrees	`canonicaldeg(n)`	Converts angle in degrees to value in range −180 to 180.

Logarithmic Functions

Operation	Usage	Notes
Exponential function	`exp(n)`	Euler's number raised to `n`.
Natural Log	`log(n)`	`n` > 0
Log (base 10)	`log10(n)`	`n` > 0

Combinatoric Functions

Operation	Usage	Notes
Combinations C(`n`,`k`)	`combination(n,k)`	Returns the number of sets of `k` elements that can be picked from an `n`-element set.
Permutations P(`n`,`k`)	`permutation(n,k)`	Returns the number of unique (ab is different from ba) sets of `k` elements that can be picked from an `n`-element set.
Factorial (`n`!)	`factorial(n)`	`n` must be an integer from 1 through 100.