450 likes | 665 Views
4.3 Graphing Quadratic Equations and its Transformations. Ms. Lilian Albarico. Quadratic Function. The graph produced by y = x 2 is a curve called a parabola. The parabola is a symmetrical curve that has one axis of symmetry.
E N D
4.3Graphing Quadratic Equations and its Transformations Ms. LilianAlbarico
Quadratic Function The graph produced by y = x2 is a curve called a parabola. The parabola is a symmetrical curve that has one axis of symmetry. The axis of symmetry is a vertical line that passes through the turning point of the parabola. The turning point is called the vertex. The equation of the axis of symmetry is x = the value of the x co-ordinate of the vertex. Every parabola that is graphed is this standard curve with transformations performed on it.
y x Quadratic Function
Transformations: • Vertical Reflection (Reflection in the x-axis) • Vertical Stretch • Vertical Translation/Shift • Horizontal Translation/Shift
Key Terms: • Mapping notation – a notation that describes how a graph and its image are related x2 -------> (x, y) • reflection in x-axis – a transformation that vertically flips the graph of a curve in the x-axis • vertical stretch – a transformation that describes how the y-values of a curve are stretched by a scale factor • vertical translation – a transformation that describes the number of units and the direction that a curve moves vertically from the origin • horizontal translation – a transformation that describes the number of units and the direction that a curve moves horizontally from the origin
Vertical Reflection • Vertical Reflection (V.R.) – a transformation in which a plane figure flips over vertically and has a horizontal axis of reflection. Also called as Reflection in x-axis.
Vertical Reflection y=x2 (x, y) y=-x2 (x, -y)
Vertical Reflection Draw the following quadratic equations, then write the mapping notations and include a table with 5 values: • f(x) = x2 and -f(x) = x2 • f(x) = 4x2 and -f(x) = 4x2 • f(x) = 1/4x2 and - f(x) = 1/4x2
Vertical Stretch • Vertical Stretch (V.S.) – a transformation that describes how the y – value is stretched by a scale factor (the number times y)
Vertical Stretch 1/2x2 (x, 2y) 2x2 (x, 1/2y)
Vertical Stretch Draw the following quadratic equations, then write the mapping notation and include a table with 5 data values: • f(x) = x2 2y = x2 1/3y= x2 • 3y = x2 4y= x2 1/4y = x2 3/4y = x2
Homework • CYU # 5 on page 175 • CYU # 8, 9, 10,11 ,12 , and 13 on pages 177-178.
Vertical Translation • Vertical Translation (V.T.) - a transformation that describes the number of units and direction that a curve has moved vertically.
Vertical Translation x2 + 1 (x, y-1) x2-1 (x, y+1)
Vertical Translation Draw the following quadratic equations, then write the mapping notation and include a table with 5 data values: • y = x2 y + 2 = x2 y-2 = x2 • y-3 = x2 (y+3)= -x2 y-1/2 = x2 y+1/2 = 2x2
Horizontal Translation • Horizontal Translation (H.T.) – a transformation that describes the number of units and direction that a curve has moved horizontally.
Horizontal Translation (x+1)2 (x-1, y) (x-1)2 (x+1, y)
Horizontal Translation Draw the following quadratic equations, then write the mapping notation and include a table with 5 data values: • y = x2 y = (x+3)2 y = (x-4)2 • y = 2(x+3)2-y= (x-2)2 2y = (x-2)2 y-1 = (x+1)2
HOMEWORK • CYU #14 AND 14 ON PAGE 179 • CYU # 18, 20, 21, 22, and 23 on page 181 – 182.
Learning Check: • When you see a –y in the equation then the image is a _________________ in the x-axis. • “When I see a 3y in the equation, then I know that there is a vertical stretch of ___________.” • The vertical stretch factor is the _________ of the coefficient of y. • “When I see y+2 in the equation, then I know that there is vertical translation of ____ units _____”. • “When I see y-3 in the equation, then I know that there is vertical translation of ____ units _____”. • The vertical translation is the ___________of the number being added to the y. • “When I see x+3 in the equation, then I know that there is horizontal translation by ____ units to the _____”. • “When I see x-4 in the equation, then I know that there is horizontal translation by ____ units to the _____”. • The horizontal translation is the ___________ of the number being added to the x.”
1) Graph the following quadratic functions and write down their mapping notations: • -y = (x+2)2 • -2y = (x-1)2 • y = (x-3)2
2) Based from the mapping notation below, write the quadratic equation and the draw its graph transformation: • (x , y) (x+2, y) • (x, y) (x+6, y-1) • (x, y) (x-1/2, y – 3/2) • (x, y) (x-2, -2y)
Absolute Value Functions absolute value – the absolute value of a number is the number without its sign |n| = n, |-n| = n. If absolute value is related to a number line, then it indicates the measure of the distance between a point and its origin without reference to direction. Absolute value functions are graphed using y = |x| after the transformations have been applied.
VERTICAL TRANSLATION y – q = |x| (x, y+q) For example: y-3 = |x| y+5= |x|
HORIZONTAL TRANSLATION y = |x-p| (x+p, y) For example: y = |x-3| y= |x+4|
VERTICAL STRETCH cy = |x| (x, 1/3y) For example: 1/2y = |x| 2y= |x|
REFLECTION in X-AXIS -y = |x| (x, -y) For example: y = -1/10|x| 1/10y= |x|
1) Graph the following absolute value functions and write its mapping notation: • -1/2 (y+3) = |x+5| • y-3 = |x+3| • 1/4y= |x-2|
2) Write the absolute value functions of the following mapping notation and graph its transformation: • (x , y) (x+1, y) • (x, y) (x, y-4) • (x, y) (x-3, y + 3) • (x, y) (-x, y+5)
Assignment • You will draw a shape using different kinds of graphs – linear, quadratic, exponential, and absolute value functions. There should only be one point of origin. Make sure your graphs are clear and accurate. Be as creative as you can. • Below your graph: • A) State the domain and range of your different graphs. • B) If it is either quadratic or absolute value functions, write its mapping notations. • Deadline : December 26, 2012
Homework • FOCUS QUESTIONS # 30 and 31 on page 186. • CYU # 33, 34, 35, 36 and 37 on pages 187-189.