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Unit 6 – Chapter 10. Unit 6. Chapter 9 Review and Chap. 9 Skills Section 10.1 – Graph y = ax 2 + c Section 10.2 – Graph y = ax 2 + bx +c Section 10.3 – Solve Quadratic Eqns by Graphing Section 10.4 – Solve Quad. Eqns. w/Square roots Section 10.6 – Solve Quad. Eqns. With Quad. Formula
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Unit 6 • Chapter 9 Review and Chap. 9 Skills • Section 10.1 – Graph y = ax2 + c • Section 10.2 – Graph y = ax2 + bx +c • Section 10.3 – Solve Quadratic Eqns by Graphing • Section 10.4 – Solve Quad. Eqns. w/Square roots • Section 10.6 – Solve Quad. Eqns. With Quad. Formula • Section 10.7-10.8 – Compare Linear, Exponential, and Quadratic Models
1. The x-coordinate of a point where a graph crosses the x-axis is a (n) . ? ? x-intercept ANSWER = = 2. A(n)is a function of the formy = a bxwhere a 0,b > 0, and b 1. exponential function ANSWER Prerequisite Skills VOCABULARY CHECK Copy and complete the statement.
3. ANSWER Prerequisite Skills SKILLS CHECK Draw the blue figure. Then draw its image after a reflection in the red line.
ANSWER 4. Prerequisite Skills SKILLS CHECK Draw the blue figure. Then draw its image after a reflection in the red line.
Prerequisite Skills SKILLS CHECK Graph y1 = x and y2 = x – 5. Describe the similarities and differences in the graphs. ANSWER • Graphs are • Parallel • Have the same • Slope • Y2 is translated • Down 5 units
ANSWER domain: all real numbers; range: all positive real numbers ANSWER Lesson 10.1, For use with pages 628-634 1.Graph the functiony = 2x. • Identify the domain and range of your graph in • Exercise 1.
domain: all real numbers; range: all positive real numbers ANSWER Lesson 10.1, For use with pages 628-634 1.Graph the functiony = x2. ANSWER • Identify the domain and range of your graph in • Exercise 1.
domain: all real numbers; range: all positive real numbers ANSWER Lesson 10.1, For use with pages 628-634 1.Graph the functiony = 3x2. ANSWER • Identify the domain and range of your graph in • Exercise 1.
domain: all real numbers; range: all positive real numbers ANSWER Lesson 10.1, For use with pages 628-634 1.Graph the functiony = (0.1)x2. ANSWER • Identify the domain and range of your graph in • Exercise 1.
domain: all real numbers; range: all positive real numbers > 2 ANSWER Lesson 10.1, For use with pages 628-634 1.Graph the functiony = x2 + 2 ANSWER • Identify the domain and range of your graph in • Exercise 1.
domain: all real numbers; range: all negative numbers ANSWER Lesson 10.1, For use with pages 628-634 1.Graph the functiony = (-1)x2 ANSWER • Identify the domain and range of your graph in • Exercise 1.
Vocabulary – 10.1 • Vertex of a Parabola • Lowest (or highest) point on a parabola • Axis of symmetry • Line that passes through the vertex • Divides the parabola into two symmetric parts • Quadratic Function • Non-linear function in the form y = ax2 + bx + c where a ≠ 0 • Parabola • U – shaped graph of a quadratic function • Parent quadratic function • Y = x2
Notes – 10.1 – Graph y = ax2 + c • All Quadratic Function graphs look like what? • A parabola • What happens to the shape of the parabola if a >1? • It is a vertical stretch • It gets skinny! • What happens to the shape of a parabola if a < 1? • Vertical shrink • It gets fat (or “fluffy”!)! • What happens if a < 0? • The graph curves down. • What effect does “c” have on the graph of the function? • It translates it up or down.
Graph y= ax2 where a > 1 EXAMPLE 1 STEP 1 Make a table of values for y =3x2 STEP 2 Plot the points from the table.
Graph y= ax2 where a > 1 EXAMPLE 1 STEP 3 Draw a smooth curve through the points. STEP 4 Compare the graphs of y = 3x2and y = x2. Both graphs open up and have the same vertex, (0, 0), and axis of symmetry,x = 0. The graph of y = 3x2 is narrower than the graph of y =x2 because the graph of y = 3x2 is a vertical stretch (by a factor of 3) of the graph of y =x2.
Graph y =ax2 where a < 1 – x2. Graph y= Compare the graph with the graph of 1 1 y = x2. 4 4 – x2. Make a table of values for y = EXAMPLE 2 STEP 1
Graph y =ax2 where a < 1 EXAMPLE 2 STEP 2 Plot the points from the table. STEP 3 Draw a smooth curve through the points.
Graph y =ax2 where a < 1 1 1 1 4 4 4 andy =x2. Compare the graphs ofy = 1 – Both graphs have the same vertex (0, 0), and the same axis of symmetry,x = 0. However, the graph of x2. 4 – – x2. x2. is wider than the graph of y =x2 and it opens down. This is because the graph of is a vertical shrink with a refl ection in the x-axis of the graph of y =x2. by a factor of y = y = EXAMPLE 2 STEP 4
EXAMPLE 3 Graph y = x2 + c Graph y = x2+ 5. Compare the graph with the graph of y = x2. STEP 1 Make a table of values for y =x2+ 5.
EXAMPLE 3 Graph y = x2 + c STEP 2 Plot the points from the table. STEP 3 Draw a smooth curve through the points.
EXAMPLE 3 Graph y = x2 + c STEP 4 Compare the graphs of y = x2+ 5and y = x2.Both graphs open up and have the same axis of symmetry, x = 0. However, the vertex of the graph of y =x2+ 5,(0, 5), is different than the vertex of the graph of y =x2,(0, 0), because the graph of y =x2 + 5 is a vertical translation (of 5 units up) of the graph of y =x2.
for Examples 1, 2 and 3 GUIDED PRACTICE Graph the function. Compare thegraph with the graph ofx2. 1. y=–4x2 STEP 1 Make a table of values for y = –4x2
for Examples 1, 2 and 3 GUIDED PRACTICE STEP 2 Plot the points from the table. STEP 3 Draw a smooth curve through the points.
2. y = x2 Make a table of values for y = x2 1 1 3 3 for Examples 1, 2 and 3 GUIDED PRACTICE STEP 1
for Examples 1, 2 and 3 GUIDED PRACTICE STEP 2 Plot the points from the table. STEP 3 Draw a smooth curve through the points.
for Examples 1, 2 and 3 GUIDED PRACTICE 3. y =x2 +2 STEP 1 Make a table of values for y = x2 +5
for Examples 1, 2 and 3 GUIDED PRACTICE STEP 2 Plot the points from the table. STEP 3 Draw a smooth curve through the points.
Graphy=x2–4.Compare the graph with the graph ofy=x2. Make a table of values fory=x2–4. 1 1 2 2 EXAMPLE 4 Graphy=ax2+c STEP1
EXAMPLE 4 Graph y = ax2 + c STEP2 Plot the points from the table. STEP3 Draw a smooth curve through the points.
Compare the graphs ofy=x2–4 andy=x2.Both graphs open up and have the same axis of symmetry, x = 0.However,the graph of y =x2– 4is wider and has a lower vertex than the graph of y =x2because the graph ofy =x2is a vertical shrink and a vertical translation of the graph of y=x2. 1 1 1 2 2 2 EXAMPLE 4 Graph y = ax2 + c STEP4
for Example 4 GUIDED PRACTICE Graph the function. Compare thegraph with the graph ofx2. 4. y= 3x2 – 6 STEP1 Make a table of values fory=3x2 – 6.
for Example 4 GUIDED PRACTICE STEP2 Plot the points from the table. STEP3 Draw a smooth curve through the points.
for Example 4 GUIDED PRACTICE 5. y= –5x2 +1 STEP1 Make a table of values fory=–5x2 +1.
for Example 4 GUIDED PRACTICE STEP2 Plot the points from the table. STEP3 Draw a smooth curve through the points.
6.y=x2–2. Make a table of values fory=x2–2. 3 3 4 4 for Example 4 GUIDED PRACTICE STEP1
for Example 4 GUIDED PRACTICE STEP2 Plot the points from the table. STEP3 Draw a smooth curve through the points.
The graph would shift 2 units up. A The graph would shift 4 units up. B The graph would shift 4 units down. C The graph would shift 4 units to the left. D EXAMPLE 5 Standardized Test Practice How would the graph of the function y = x2 + 6 be affected if the function were changed to y = x2 + 2?
ANSWER The correct answer is C. A D B C EXAMPLE 5 Standardized Test Practice SOLUTION The vertex of the graph of y = x2 + 6 is 6 units above the origin, or (0, 6). The vertex of the graph of y = x2 + 2 is 2 units above the origin, or (0, 2). Moving the vertex from (0, 6) to (0, 2) translates the graph 4 units down.
EXAMPLE 6 Use a graph SOLAR ENERGY A solar trough has a reflective parabolic surface that is used to collect solar energy. The sun’s rays are reflected from the surface toward a pipe that carries water. The heated water produces steam that is used to produce electricity. The graph of the function y = 0.09x2 models the cross section of the reflective surface where xandyare measured in meters. Use the graph to find the domain and range of the function in this situation.
EXAMPLE 6 Use a graph SOLUTION STEP 1 Find the domain. In the graph, the reflective surface extends 5 meters on either side of the origin. So, the domain is 5 ≤ x ≤ 5. STEP 2 Find the range using the fact that the lowest point on the reflective surface is (0, 0) and the highest point, 5, occurs at each end. y = 0.09(5)2= 2.25 Substitute 5 for x. Then simplify. The range is 0≤ y ≤ 2.25.
Describe how the graph of the function y = x2+2 would be affected if the function were changed to y=x2– 2. 7. ANSWER The graph would be translated 4 unit down. for Examples 5 and 6 GUIDED PRACTICE SOLUTION The vertex of the graph of y = x2 + 2 is 6 units above the origin, or (0, 2). The vertex of the graph of y = x2 – 2 is 2 units down above the origin, or (0, – 2). Moving the vertex from (0, 2) to (0, – 2) translates the graph 4 units down.
What if In example 6 ,suppose the reflective surface extends just 4 meters on either side of the origin.Find the range of the function in this situation. 8. for Examples 5 and 6 GUIDED PRACTICE SOLUTION STEP 1 Find the domain. In the graph, the reflective surface extends 4 meters on either side of the origin. So, the domain is – 4 ≤ x ≤ 4.
for Examples 5 and 6 GUIDED PRACTICE STEP 2 Find the range using the fact that the lowest point on the reflective surface is (0, 0) and the highest point 4, occurs at each end. y = 0.09(4)2= 144 Substitute 5 for x. Then simplify. The range is – 4 ≤ x ≤ 4, 0 ≤y ≤1.44.
7 ANSWER 17 ANSWER Lesson 10.2, For use with pages 635-640 Evaluate the expression. 1.x2– 2 whenx = 3 2. 2x2 + 9 whenx = 2
3. Martin is replacing a square patch of counter top. The area of the patch is represented by A = s2. What is the area of the patch if the side length is 2.5 inches? 6.25 in.2 ANSWER Lesson 10.2, For use with pages 635-640 Evaluate the expression.
Vocabulary –10.2 • Maximum Value • Highest possible value of a graph • Not all graphs have a maximum value • Minimum Value • Smallest possible value of a graph • Not all graphs have a minimum value • Vertex • AKA the “maximum” or “minimum” value of a parabola