Polynomial Key Features
**Part I — Identifying Key Features of Polynomial Functions**
1. Given each polynomial function, find its factored form, leading coefficient, degree, and end behavior.
2. For $(x - 2)(x^2 + 3x + 4)$:
- Factored form: Already factored.
- Leading coefficient: The $x^2$ term in second factor has leading coefficient 1, multiplied by 1 from $(x - 2)$, so overall positive.
- Degree: $1 + 2 = 3$ (since multiplied linear by quadratic).
- End behavior:
- Leading term approx $x^3$ positive, so as $x \to -\infty$, $f(x) \to -\infty$ (falls left).
- As $x \to \infty$, $f(x) \to \infty$ (rises right).
3. $(3x + 1)(x - 4)(x + 2)$:
- Factored form: given.
- Leading coefficient: $3 \times 1 \times 1 = 3 > 0$ positive.
- Degree: $1 + 1 + 1 = 3$ cubic.
- End behavior: cubic with positive leading coefficient.
- Left: $f(x) \to -\infty$.
- Right: $f(x) \to \infty$.
4. $-x^3 + 5x^2 - 3x + 2$:
- Factored form: not given; leading term is $-x^3$ so leading coefficient $-1$.
- Degree: 3.
- End behavior:
- Left: since degree odd and leading coefficient negative, $f(x) \to \infty$.
- Right: $f(x) \to -\infty$.
5. $4x^4 - 2x^2 + x - 6$:
- Leading coefficient 4, positive.
- Degree 4 (even).
- End behavior even degree positive leading:
- Left: $\infty$
- Right: $\infty$
6. $(x + 5)(x - 3)(x - 1)$:
- Leading coefficient: $1\times 1\times 1 = 1 > 0$.
- Degree 3.
- End behavior odd degree positive leading:
- Left: $-\infty$
- Right: $\infty$
7. $2(x - 1)^2(x + 4)$:
- Degree: $(2) + 1 = 3$ (quadratic factor squared plus linear).
- Leading coefficient: $2\times 1^2 \times 1 = 2 > 0$.
- End behavior odd degree positive:
- Left: $-\infty$
- Right: $\infty$
8. $-3x^5 + 7x^3 - x + 10$:
- Degree 5.
- Leading coefficient $-3 < 0$.
- End behavior odd degree negative leading:
- Left: $\infty$
- Right: $-\infty$
9. $(x - 2)^3(x + 1)^2$:
- Degree $3 + 2 = 5$.
- Leading coefficient: $1^3 \times 1^2 = 1 > 0$.
- End behavior odd degree positive:
- Left: $-\infty$
- Right: $\infty$
10. $5x^4 - 2x^3 + 6x - 1$:
- Degree 4, leading coefficient 5 positive.
- End behavior even degree positive:
- Left: $\infty$
- Right: $\infty$
11. $-2x^6 + 4x^3 - x^2 + 9$:
- Degree 6 even.
- Leading coefficient $-2 < 0$ negative.
- End behavior even degree negative:
- Left: $-\infty$
- Right: $-\infty$
12. $(x + 2)^4(x - 3)$:
- Degree $4 + 1 = 5$ odd.
- Leading coefficient $1^4 \times 1 = 1 > 0$ positive.
- End behavior odd degree positive:
- Left: $-\infty$
- Right: $\infty$
13. $(x - 1)^2(x + 1)^2(x - 2)$:
- Degree $2 + 2 + 1 = 5$ odd.
- Leading coefficient $1^2 \times 1^2 \times 1 = 1 > 0$ positive.
- End behavior odd positive:
- Left: $-\infty$
- Right: $\infty$
**Part II — Zeros, Multiplicity, Behavior**
A. For each function:
1. $(x - 2)^2(x + 1)$:
- Zeros: 2, -1
- Multiplicity: 2 (at 2), 1 (at -1)
- Characteristic: Even multiplicity at 2 (touches x-axis), odd multiplicity at -1 (crosses)
- Behavior: Graph touches x-axis at 2 and bounces, crosses at -1.
2. $(x + 3)(x - 1)^3$:
- Zeros: -3, 1
- Multiplicity: 1 (at -3), 3 (at 1)
- Characteristic: Crosses at -3 linear, crosses with flattening at 1 cubic.
3. $(x - 4)(x + 2)^2(x - 1)$:
- Zeros: 4, -2, 1
- Multiplicity: 1 (4), 2 (-2), 1 (1)
- Behavior: crosses at 4 and 1, touches and bounces at -2.
4. $(x + 1)^4(x - 2)$:
- Zeros: -1, 2
- Multiplicity: 4 (at -1), 1 (at 2)
- Behavior: touches and flattens at -1, crosses at 2.
5. $x(x - 3)^2(x + 4)$:
- Zeros: 0, 3, -4
- Multiplicity: 1 (0), 2 (3), 1 (-4)
- Behavior: crosses at 0 and -4, touches and bounces at 3.
6. $(x + 2)^3(x - 1)(x - 5)$:
- Zeros: -2, 1, 5
- Multiplicity: 3 (-2), 1 (1), 1 (5)
- Behavior: crosses with flattening at -2, crosses at 1 and 5.
B. Compute $P(x)$ values:
1. $P(x) = x(x - 2)(x + 1)^2(x - 3)$:
- For each $x$:
- $P(-3) = (-3)(-5)(-2)^2(-6) = (-3)(-5)(4)(-6) = (-3 imes -5) imes 4 imes -6 = 15 imes 4 imes -6 = 60 imes -6 = -360$
- $P(-1) = (-1)(-3)(0)^2(-4) = 0$
- $P(0) = 0$
- $P(1) = (1)(-1)(2)^2(-2) = 1 imes (-1) imes 4 imes (-2) = (-1) imes 4 imes (-2) = -4 imes (-2) = 8$
- $P(2) = (2)(0)(3)^2(-1) = 0$
- $P(3) = (3)(1)(4)^2(0) = 0$
2. $P(x) = (x + 2)(x - 1)(x - 3)^2$:
- $P(-2) = 0$
- $P(0) = (2)(-1)(-3)^2 = 2 imes -1 imes 9 = -18$
- $P(1) = (3)(0)(-2)^2 = 0$
- $P(2) = (4)(1)(-1)^2 = 4 imes 1 imes 1 = 4$
- $P(3) = (5)(2)(0)^2 = 0$
- $P(4) = (6)(3)(1)^2 = 6 imes 3 imes 1 = 18$
3. $P(x) = (x - 4)^2(x + 1)^3$ (values not requested to compute).