POLY returns a floating-point value that is an approximation of a polynomial formed from an one-dimensional array expressions x. The returned value has the same attributes as the first argument. The syntax for POLY is:
x must be REAL FLOAT and y is converted to the attributes of x, if necessary.
x(0) + x(1)*y + x(2)*y**2 + ... + x(n)*y**n
x(m) + x(m+1)*y + x(m+2)*y**2 + ... + x(n)*y**(n-m)