Most chordates are vertebrates. Invertebrate chordates, which belong to two of the subphyla of chordatesâCephalochordata and Urochordata, also have a dorsal tubular nerve cord, a notochord, pharyngeal pouches, a postanal tail, and, possibly, an ancestral thyroid gland.They ha ve no backbone, however.ost chordates are vertebrates. Invertebrate chordates, which belong to two of the subphyla of chordatesâCephalochordata and Urochordata, also have a dorsal tubular nerve cord, a notochord, pharyngeal pouches, a postanal tail, and, possibly, an ancestral thyroid gland. They ha ve no backbone, however.
Quadratic Equation. An equation where the highest exponent of the variable (usually x) is a square (2). It is usually written ax2+bx+c = 0 Example: 2x2+5x-3 = 0. See: Exponent. Quadratic Equations.
In mathematics, a quadratic is a type of problem that deals with a variable multiplied by itself â an operation known as squaring. This language derives from the area of a square being its side length multiplied by itself.