Soru
Find the unique polynomial P(x) of degree 2 or less such that P(1)=1,P(3)=27,P(4)=64 using each of the following methods : (i) Lagrange interpolation formula:
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Kıdemli · 12 yıl öğretmeni
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To find the unique polynomial \( P(x) \) of degree 2 or less that satisfies the given conditions using the Lagrange interpolation formula, we can follow these steps:1. **Identify the given points:**
2. **Lagrange interpolation formula:** The Lagrange interpolation formula for a polynomial \( P(x) \) of degree 2 passing through points \((x_0, y_0)\), \((x_1, y_1)\), and \((x_2, y_2)\) is given by:
where \( L_i(x) \) are the Lagrange basis polynomials defined as:
3. **Calculate the Lagrange basis polynomials:**
4. **Form the polynomial \( P(x) \):**
Substitute the expressions for \( L_0(x) \), \( L_1(x) \), and \( L_2(x) \):
5. **Simplify the polynomial:**
Factor out common terms:
Simplify the expression inside the brackets:
Combine like terms:
Simplify further:
Combine like terms: