SKEDSOFT

Maths For Engineers - 3

Fitting a Curve of Different Types:

Fitting a Curve of Type Y = AX BX2

Let (xi,yi), i = 1,2.......,n be the n - sets of given values. Then the residual at x = xi is given by

           

Introducing quantity U such that,

       

By the principle of least squares, U is minimum, Then

Solving the above equation we get a and b.

Fitting a Curve of Type XY = A BX

Let the given n point be (x1,y1) , (x2,y2).........(xn,yn). Rearranging the given equation, we have

Then the residual at x = xi is

Introducing quantity u such a way that,

By the priciple of least square, we have

From the above equation we get the value of a and b.