DERIV2: Second Derivative function

syntax: DERIV2(expr, varname, value) or
DERIV2(expr, varname, value, prec)

returns the approximate second derivative of <expr> with respect to variable <varname> given the <value> at which to calculate the second derivative and the (optional) precision <prec> to calculate up to. As <prec> gets smaller, the approximation usually gets more accurate The central difference formula method is used for this function