GRAPHING EQUATIONS BY TYPE AND WITH POINTS By Mr. Barnard
OBJECTIVE: Know the shape of a graph from its equation and sketch a graph by plotting points.
LIFE EXPECTANCY
AGE OF MOTHER WITH FIRST BORN
PROBABILITY OF FIRST MARRIAGE
BIRTHS TO UNMARRIED WOMEN
TYPES OF GRAPHS
Linear: y = x
Quadratic: y = x 2
Cubic: y = x 3
Square Root:
Logarithms: y= logx y= lnx
y= sinx y= cosx Trigonometry:
y= tanx y= cotx Trigonometry:
y= secx y= cscx
Absolute Value: y = |x|
COORDINATE PLANE
X-axis Y-axis Quadrants Origin III III IV Ordered Pair
PRACTICE GRAPHING USE YOUR WHITE BOARD, ERASER, AND MARKER
y = 5x - 2
y = 2x 2 + 1
y = 3x 3 – 2x 2 - 1
y = 5sin2x Plug in radian values for x!
INTERCEPTS
X-intercept Y-intercept Values where a line or curve crosses the x-axis. (y = 0) Values where a line or curve crosses the y-axis. (x = 0)
Determine the x & y intercepts for: y = x y = x y = 6x 3 + 4x 2
Which equation matches the graph? y= 3x – 5 y= 2x 2 – 5 y= 5x y= x3 x3 - 5
SYMMETRY The quality of having balance or exact parts of a figure on either side of an axis.
EXAMPLES OF SYMMETRY
MORE EXAMPLES OF SYMMETRY
LOOK AROUND… SYMMETRY… IT’S ALL AROUND YOU RIGHT NOW!
X-axis symmetry: can replace y with –y and produce the same equation. Y-axis symmetry: can replace x with –x and produce the same equation. Origin symmetry: can replace x with –x AND y with –y and produce the same equation. TYPES OF SYMMETRY
Prove and disprove the type of symmetry for each: y = x y = -x y = x 4 - 2
Even function: symmetric with the y-axis Odd function: symmetric with the origin What type of function is symmetric with the x-axis?
Using y = x 3 - x 2, determine the x-intercepts (show evidence) y-intercepts (show evidence) type of symmetry (prove and disprove) graph (use intercepts, symmetry, & other points
SKETCH A GRAPH: Quadratic Equation X-axis Symmetry X-intercept at –2 Y-intercept at 3 (3, 4)
SKETCH A GRAPH: Quadratic Equation Y-axis Symmetry X-intercept at 3 Y-intercept at 2 (-5, -2)
SKETCH A GRAPH: Cubic Equation Origin Symmetry X-intercept at –4 Y-intercept at 0 (-2, 2) and (-6, -4)
SUGGESTED PRACTICE: Page 8 (1-12, 20, 32, 39-42, 44-47, 51, 54)