Graphs of Cubic Functions

The general form of a cubic function is y = ax³ + bx + cx + d where a , b, c and d are real numbers and a is not zero.

Example:

Draw the graph of y = x³ + 3 for –3 ≤ x ≤ 3. Use your graph to find
a) the value of y when x = 2.5
b) the value of x when y = –15

Solution:

a) When x = 2.5, y 18.6

b) When y = –15, x –2.6

Example:

Plot the graph of y = x³ – 9x + 5 for –4 „ x „ 4 and use your graph to find:
a) the value of y when x = 1.6
b) the value of x when y = 12

Solution:

a) When x = 1.6, y –5.3

b) When y = 12, x –0.8, or x –2.5

Videos

Graphing some important functions - Ploting points. linear function, quadratic function, cubic function, square root function, absolute value function
Professor Edward Burger explains graphing some important functions

Stretching a graph - Parabola shapes and cubic shapes
Professor Edward Burger explains stretching a graph.

Matching equations with their graphs -
Professor Edward Burger explains matching equations with their graphs

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