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Graph Cubic Functions Lesson 3.1 Page 126. Vocabulary :. A cubic function is a nonlinear function that can be written in the standard form y = ax 3 + bx 2 + cx + d where a ≠ 0. A function f is an odd function if f (- x ) = - f ( x ).
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Vocabulary: • A cubic functionis a nonlinear function that can be written in the standard form y =ax3 + bx2 + cx + d where a ≠ 0. • A function f is an odd functionif f (-x) = -f (x). • The graphs of odd functions are symmetric about the origin. • A function f is an even functionif f (-x) = f (x). • The graphs of even functions are symmetric about the y-axis.
Even Function Y – Axis SymmetryFold the y-axis (x, y) (-x, y) (x, y) (-x, y)
Test for an Even Function • A function y = f(x) is even if , for each x in the domain of f. f(-x) = f(x) Symmetry with respect to the y-axis
Symmetry with respect to the origin (x, y) (-x, -y) (2, 2) (-2, -2) (1, -2) (-1, 2) Odd Function
Test for an Odd Function • A function y = f(x) is odd if , for each x in the domain of f. f(-x) = -f(x) Symmetry with respect to the Origin
Tests for Even and Odd Functions • Even: f(-x) = f(x) • Odd: f(-x) = -f(x) • Both begin with f(-x)
End Behavior • The end behavior of a function’s graph is the behavior of the graph as x approaches positive infinity (+∞) or negative infinity (-∞). • If the degree is odd and the leading coefficient is positive: f (x) → - ∞ as x → - ∞ and f (x) → +∞ as x → +∞ . • If the degree is odd and the leading coefficient is negative: f (x) → + ∞ as x → - ∞ and f (x) → - ∞ as x → +∞ . Right Left Down Left Right Up Up Left Down Right
Up If the degree is odd and the leading coefficient is positive:f (x) → - ∞ as x → - ∞andf (x) → +∞ as x → +∞ . Left Right Down
Up If the degree is odd and the leading coefficient is negative:f (x) → + ∞ as x → - ∞ andf (x) → - ∞ as x → ∞ . Left Right Down
The following slides provide practice problems on this lesson. Use these examples to help you with your homework!
Homework Assignment: Page 128 # 1 – 6, 10 – 15 allPage 129 # 1 – 3, 5 – 11 all