Back to Exercise: Graph polynomial functions

Exercises: Graph Polynomial Functions, Identifying Zeros and Showing End Behavior

Work through each section in order. Show your work where indicated.

Grade 9·20 problems·~30 min·Common Core Math - HS Functions·standard·hsf-if-c-7c
Work through problems with immediate feedback
A

Recall / Warm-Up

1.

What are the zeros of f(x)=(x3)(x+5)f(x) = (x - 3)(x + 5)?

2.

Factor f(x)=x39xf(x) = x^3 - 9x. What are the zeros?

3.

Which of the following is TRUE about polynomial functions?

B

Fluency Practice

1.

What are the zeros of g(x)=(x+1)(x2)(2x6)g(x) = (x + 1)(x - 2)(2x - 6)?

2.

How many zeros does f(x)=x(x2+1)(x4)f(x) = x(x^2 + 1)(x - 4) have (counting real zeros only)?

3.

What is the degree of f(x)=(x+3)2(x1)(x4)3f(x) = (x + 3)^2(x - 1)(x - 4)^3?

4.

What is the end behavior of f(x)=3x4+7x2x+100f(x) = -3x^4 + 7x^2 - x + 100?

5.

What is the end behavior of f(x)=2x510x3+xf(x) = 2x^5 - 10x^3 + x?

C

Varied Practice

1.

Which end behavior matches f(x)=(x1)(x+2)(x5)f(x) = -(x - 1)(x + 2)(x - 5)?

2.

A polynomial of degree 5 has how many turning points at most?

3.

The function f(x)=(x2)2(x+1)f(x) = (x - 2)^2(x + 1) has zeros at x=2x = 2 and x=1x = -1. What happens at each zero?

4.

The polynomial f(x)=(x+4)3(x2)2f(x) = (x + 4)^3(x - 2)^2 has degree 5. How many distinct xx-intercepts (real zeros) does its graph show?

D

Word Problems

1.

A polynomial is given in factored form: f(x)=(x+3)(x1)2(x5)f(x) = -(x + 3)(x - 1)^2(x - 5).

(a) List all zeros and state the multiplicity of each.
(b) At each zero, does the graph cross or bounce?
(c) What is the degree? What are the maximum number of turning points?
(d) Describe the end behavior.

2.

A polynomial function gg has degree 4, a negative leading coefficient, zeros at x=2x = -2 (multiplicity 2), x=1x = 1 (multiplicity 1), and x=3x = 3 (multiplicity 1).

1.

Write a factored-form equation for gg that matches the given information.

2.

Describe the graph behavior at each zero and the end behavior. How many turning points does the graph have at most?

3.

A polynomial function is given: f(x)=x45x2+4f(x) = x^4 - 5x^2 + 4.

(a) Factor completely and identify all real zeros.
(b) State the end behavior and the maximum number of turning points.
(c) Describe the crossing/bouncing behavior at each zero.

E

Error Analysis

1.

A student is asked: "How many turning points does f(x)=x53x3+xf(x) = x^5 - 3x^3 + x have?" The student answers: "It has degree 5, so it has exactly 5 turning points."

What is wrong with the student's reasoning?

2.

A student graphs f(x)=(x3)2(x+1)f(x) = (x - 3)^2(x + 1) and draws the graph crossing the xx-axis at both x=3x = 3 and x=1x = -1.

What mistake did the student make at x=3x = 3?

F

Challenge / Extension

1.

Find a polynomial of degree 5 with exactly two distinct xx-intercepts, where the graph bounces at one and crosses at the other. Write the function in factored form and describe all key features (zeros, multiplicities, end behavior, maximum number of turning points).

2.

Without graphing, explain how you know that f(x)=x3+1f(x) = x^3 + 1 has exactly one real xx-intercept. Identify it and describe the end behavior of the graph.

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