Show that you know what the “normal equations” are. You can explain, derive, describe, or whatever; but keep your answer direct to the point and simple. If you did not know the phenomenological...

Show that you know what the “normal equations” are. You can explain, derive, describe, or whatever; but keep your answer direct to the point and simple.

If you did not know the phenomenological functional form of a relation, you could use a power series expression, ρ = a + bT + cT²
+ dT³
+ … to generate a ρ(T) relation. How would you determine the number of terms in the power series expansion? Explain.