cta (version 1.3.0)

quadratic.fit: Quadratic Fit

Description

Fits a quadratic curve that passes all three points on the two-dimensional Euclidean space \(R^2\).

If the design matrix \(X\) of the quadratic fit has a condition number which is greater than \(10^8\), a linear regression line is fitted to the three points instead.

Usage

quadratic.fit(x, y)

Arguments

x

A vector of length three, which represents the \(x\)-values of the three points.

y

A vector of length three, which represents the \(y\)-values of the three points.

Value

quadratic.fit returns a vector of length three. The first, second, and third elements of the returned vector are the second degree, first degree, and zero-th degree coefficients, respectively, of the fitted quadratic curve, or of the fitted linear regression line.

See Also

solve_quadratic

Examples

# NOT RUN {
# Three points: (0, 1), (1, 0), (3, 4).
quadratic.fit(c(0, 1, 3), c(1, 0, 4))
# }