HP Prime Graphing Calculator - Manual (Page 403)

Functions and commands 399
logarithmic_
regression
Returns the coefficients a and b of y=a*ln(x)+b, where y is the
natural logarithm that best approximates the points whose
coordinates are the elements in two lists or the rows of a
matrix.
logarithmic_regression(Lst||Mtrx(A),[Lst])
Example:
logarithmic_regression([[1.0,1.0],[2.0,4.0],[
3.0,9.0],[4.0,16.0]])
gives
10.1506450002,-
0.564824055818
logb Returns the logarithm of base b of a.
logb(a,b)
Example:
logb(5,2)
gives
ln(5)/ln(2)
which is approximately
2.32192809489
logistic_
regression
Returns y, y', C, y'max, xmax, and R, where y is a logistic
function (the solution of y'/y=a*y+b), such that y(x0)=y0 and
where [y'(x0),y'(x0+1)...] is the best approximation of the line
formed by the elements in the list L.
logistic_regression(Lst(L),Real(x0),Real(y0))
Example:
logistic_regression([0.0,1.0,2.0,3.0,4.0],0.0
,1.0)
gives
[-17.77/(1+exp(-
0.496893925384*x+2.82232341488+3.14159265359*
i)),-2.48542227469/(1+cosh(-
0.496893925384*x+2.82232341488+3.14159265359*
i))]
lvar Returns a list of variables used in an expression.
lvar(Expr)
Example:
lvar(exp(x)*2*sin(y))
gives
[exp(x),sin(y)]
magenta Used with display to specify the color of the geometrical
object to be displayed.
map Applies a function to the elements of the list.
map(Lst,Fnc)
Example:
map([1,2,3],x->x^3)
gives
[1,8,27]