# Problems from Interpolation of Hermite

We know that: $$f (0) = 3$$, $$f'(0) = 1$$, $$f(1) = 2$$ and $$f'(1)=-2$$. Calculate the polynomial of Hermite that interpolates these points.

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### Development:

In this case we have $$n+1=2$$ points, therefore the degree of the polynomial of Hermite will be $$2n+1 = 3$$. We proceed as we explained, we write in a table the points repeating those in which we know the derivative:

 $$0$$ $$3$$ $${f'}_0=1$$ $$0$$ $$3$$ $$\dfrac{-1-1}{1-0}=-2$$ $$\dfrac{2-3}{1}=-1$$ $$\dfrac{-1+2}{1-0}=1$$ $$1$$ $$2$$ $$\dfrac{-2+1}{1-0}=-1$$ $${f'}_1=-2$$ $$1$$ $$2$$

Then, the polynomial is written in the same way, taking the first element of every column (starting from the second).

$$\begin{array}{rl} P_3(x)=& 3+1(x-0)-2(x-0)^2+1(x-0)^2(x-1)\\ =& 3+x-2x^2+x^3-x^2= x^3-3x^2+x+3 \end{array}$$\$

### Solution:

$$P_3(x)= x^3-3x^2+x+3$$

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