I need an equation that matches the attached graph. Please help. Data is below the graph.
Since there are 40 points, it would fit a polynomial of order 39 exactly.
When you substitute each point, you'll get 40 equations in 40 unknowns which you can solve using technology or MUCH difficulty by hand.
I really appreciate everyone's help with this and Captain Black, if you don't want to do it (fair enough), you can show me how to do it and then I can do it.
However the red curve in your document is not a plot of the quadratic (which is smooth)
Checking my notes, the typo is a wrong sign, it should be:
Also since you already have the equation of the trend line why are you continuing with this thread?
You could use interpolation polynomial in the Lagrange form:
Lagrange polynomial - Wikipedia, the free encyclopedia.
For p(x) you don't need to find k coefficients but you have k+1 terms of order k.
You could write a little program for p(x).