Question

For a second degree parabola equation how many normal equation are required to fit the equation

Answer 1

Step-by-step explanation:

i think this is correct and mark me as a brainliest and( thank you) if this is a right answer

Answer 2

Answer:

there will be three norma equations

Step-by-step explanation:

The second degree parabola describes the trend (non linear) in a time series where amount of change is constant per unit time.

The quadratic (parabolic)trend can be described by the  equation:-

y = a + bx + cx²

applying method of least square will gives the normal equation as,

Σy = na + bΣx + CΣx²

Σxy = aΣx + bΣx²+ Cx³

Σx²y = aΣx² + bΣx³ + cΣx⁴

However if Σx = 0

then, the normal equation will reduces to

Σy = an+ c∑x²

Σxy = b∑x²

Σx²y = a∑x² + c∑x⁴

now we can find values of a, b, and c as

c= (n∑x²y - ∑x²)(∑y)/[n∑x² - (∑x²)²]

a = (∑y - c∑x²)/n

b = ∑xy/∑x²