Math Problem Statement

solve and prrove

Find, if possible, values of a, b, c, d such that the cubic curve y = ax^3 + bx^2 + cx + d passes through the points (1, 0), (2, 1), and (3, 2) in the xy-plane.

Solution

We are tasked with finding values of aa, bb, cc, and dd for the cubic equation y=ax3+bx2+cx+dy = ax^3 + bx^2 + cx + d such that it passes through the points (1,0)(1, 0), (2,1)(2, 1), and (3,2)(3, 2).

Let's solve this step by step.

Step 1: Substituting the points into the equation.

The cubic equation is:

y=ax3+bx2+cx+dy = ax^3 + bx^2 + cx + d

Substituting the points (1,0)(1,0), (2,1)(2,1), and (3,2)(3,2) will give us a system of linear equations.

  1. For the point (1,0)(1, 0): 0=a(1)3+b(1)2+c(1)+da+b+c+d=00 = a(1)^3 + b(1)^2 + c(1) + d \quad \Rightarrow \quad a + b + c + d = 0

  2. For the point (2,1)(2, 1): 1=a(2)3+b(2)2+c(2)+d8a+4b+2c+d=11 = a(2)^3 + b(2)^2 + c(2) + d \quad \Rightarrow \quad 8a + 4b + 2c + d = 1

  3. For the point (3,2)(3, 2): 2=a(3)3+b(3)2+c(3)+d27a+9b+3c+d=22 = a(3)^3 + b(3)^2 + c(3) + d \quad \Rightarrow \quad 27a + 9b + 3c + d = 2

Now, we have the following system of equations:

1. & \quad a + b + c + d = 0 \\ 2. & \quad 8a + 4b + 2c + d = 1 \\ 3. & \quad 27a + 9b + 3c + d = 2 \end{align*}$$ ### Step 2: Solving the system. We will solve these equations to find $$a$$, $$b$$, $$c$$, and $$d$$.The general solution to the system of equations, with respect to $$d$$, is as follows: - $$a = -\frac{d}{6} - \frac{1}{6}$$ - $$b = d + 1$$ - $$c = -\frac{11d}{6} - \frac{5}{6}$$ Since $$d$$ is a free parameter, there are infinitely many solutions, depending on the value of $$d$$. This means the cubic curve can take different forms depending on the value assigned to $$d$$. Would you like further details on this, or do you have any specific questions? Here are some additional related questions to consider: 1. What would the curve look like if $$d = 0$$? 2. How does changing $$d$$ affect the shape of the cubic curve? 3. What happens if we include a fourth point to constrain the curve further? 4. How does this system demonstrate the flexibility of cubic functions? 5. Can this approach be extended to higher-degree polynomials

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Math Problem Analysis

Mathematical Concepts

Algebra
Cubic Equations
System of Linear Equations

Formulas

y = ax^3 + bx^2 + cx + d
Linear equations formed from substituting points (1,0), (2,1), (3,2)

Theorems

System of Linear Equations
Cubic Polynomial

Suitable Grade Level

Grades 10-12