FUNCTIONS
SPECIAL FUNCTIONS
OBJECTIVES:
• define piecewise defined functions;
• evaluate piecewise defined functions;
• enumerate some of the common functions that
can be defined as piecewise defined functions
• define absolute value function; and
• define greatest integer function
DEFINITION: PIECEWISE DEFINED FUNCTION
Sometimes a function is defined by more than one
rule or by different formulas. This function is called
a piecewise define function.
A piecewise defined function is defined by different
formulas on different parts of its domain.
Example: if
if x<0 if
if if
EXAMPLE:
A. Evaluate the piecewise function at the
indicated values.
if x<0 f(-2), f(-1), f(0), f(1), f(2)
if
if
if
if
f(-5), f(0), f(1),
f(5)
EXAMPLE:
B. Define g(x) = |x| as a piecewise defined
function and evaluate g(-2), g(0) and g(2).
Solution:
From the definition of |x|,
EXAMPLE:
Sketch the graph of the following functions and
determine the domain and range.
EXERCISES:
1.Compute the indicated values of the given functions.
a. b.
c.
2. Define H(x) as a piecewise defined function and
evaluate H(1), H(2), H(3), H(0) and H(-2) given by,
H(x) = x - |x – 2|.
3. For a given outside temperature T and wind speed v, the
Wind Chill Index (WCI) is the equivalent temperature that
exposed skin would feel with a wind speed of 4 mi/hr.
An empirical formula for the WCI based on experience
and observation is
where T is the air temperature in oF, v is the wind speed in
mi/hr, and WCI is the equivalent temperature in oF.
Find the WCI if the air temperature is 25oF and
a) v = 3 mi/hr,
b) v = 46 mi/hr and c) v= 15 mi/hr.
DEFINITION: ABSOLUTE VALUE FUNCTION
Recall that the absolute value or magnitude of
a real number is defined by
Properties of absolute value:
The graph of the function can be obtained
by graphing the two parts of the equation
separately. Combining the two parts produces the V-
shaped graph. It may help to generate the graph of
absolute value function by expressing the function without
using absolute values.
Example:
Sketch the graph of the following functions and determine
the domain and range.