Mathematical interpolation is "linear interpolation". The principle is that if A (I 1, B 1) and B (I 2, B2) are two points, then the point P(i, b) is on the straight line determined by the above two points. In engineering, I is between i 1 and i2, so P is between point A and point B, so it is called "linear interpolation method". Mathematical interpolation shows that the variables reflected by point P follow the linear relationship reflected by straight line AB. The above formula is easy to get. A, B and P are straight lines, then (b-b1)/(I-I1) = (B2-b1)/(I2-I1) = the slope of the straight line, and the transformation can be obtained.
And quadratic parabola interpolation method:
Let the quadratic parabola relation be y=f(x), and calculate the function at x=x0. F(x 1), f(x2) and f(x3) are known, where x 1.