l Note s 4 -1
PreC a                               IICK
                                        K
                         ctions
                                   L C !!!
                                  C L !!!
                 ial Fun
                                  C E
                                    ME
          one nt
                                    M
    Exp
GET YOUR CALCULATOR!!
Definition: Exponential Function

 The exponential function with base a
 is defined by:
              f(x) = ax

 where a > 0 and a ≠ 1.
Ex 1—Evaluating Exponential Functions
   Let f(x) = 3x and evaluate the following:
(a) f(2) = 32 = 3 ^ 2 ENTER = 9
(b) f(–⅔) = 3-⅔ =3 ^((–) 2÷3 ) ENTER

                                   ≈ 0.4807
(c) f(π) = 3π = 3^π ENTER ≈ 31.544


(d) f( √2 ) = 3√2 = 3^√ 2) ENTER ≈ 4.7288
    Hint: you will need a calculator!!
Graphs of Exponential Functions
           F(x) = ax

    Domain: All real numbers
         Range: (0, ∞)
ex 2: Identifying Graphs of Exponential Functions

   Find the exponential function f(x) = ax
          whose graph is given.

                       Since f(2) = a2 = 25,
                       we see that
                       the base is 5.
                        SO… f (x) = 5x
ex 3: Identifying Graphs of Exponential Functions

  Find the exponential function f(x) = ax
          whose graph is given.

                         Since f(3) = a3 = 1/8 ,
                         we see that
                         the base is ½ .
                            SO... f (x) = (½)x
reak ! !!!
Brain B
Speaking of Infinity…
 Make an infinity symbol with your right hand out in front of
 you. and stop your finger on the far right side of the
 infinity sign.

 Lift your left hand to be at the far left side of the infinity
 sign. Now move your hands at the same time and the
 same pace in the same direction to continue your infinity
 sign. Your hands should cross the middle at the same
 time.

 This one seems easy at first. Then you try to do it when
 your hands are doing the infinity signs in different
 directions. You should look like a choir director if you are
 doing it correctly. 
We can graph
Exponential
Functions using
transformations.


Find the parent
function f(x) = 2x
in the front of
your book.
Ex4—Transformations
 Use the graph of f(x) = 2x to sketch the
 graph of the function.
  g(x) = 1 + 2x
  Notice that the line
   y = 1 is now a horizontal
   asymptote.
Ex5 - Use the graph of f(x) = 2x to sketch the
graph of the function.

 h(x) = –2x
EX 6: Use the graph of f(x) = 2x to sketch the
  graph of the function.
k(x) = 2x –1
You have finished your Homework!!

Great job!

Now go get a cookie for yourself!


;)

Pre Calculus notes 4 1 Exponential Functions

  • 1.
    l Note s4 -1 PreC a IICK K ctions L C !!! C L !!! ial Fun C E ME one nt M Exp
  • 2.
  • 3.
    Definition: Exponential Function The exponential function with base a is defined by: f(x) = ax where a > 0 and a ≠ 1.
  • 4.
    Ex 1—Evaluating ExponentialFunctions Let f(x) = 3x and evaluate the following: (a) f(2) = 32 = 3 ^ 2 ENTER = 9 (b) f(–⅔) = 3-⅔ =3 ^((–) 2÷3 ) ENTER ≈ 0.4807 (c) f(π) = 3π = 3^π ENTER ≈ 31.544 (d) f( √2 ) = 3√2 = 3^√ 2) ENTER ≈ 4.7288 Hint: you will need a calculator!!
  • 5.
    Graphs of ExponentialFunctions F(x) = ax Domain: All real numbers Range: (0, ∞)
  • 6.
    ex 2: IdentifyingGraphs of Exponential Functions Find the exponential function f(x) = ax whose graph is given. Since f(2) = a2 = 25, we see that the base is 5. SO… f (x) = 5x
  • 7.
    ex 3: IdentifyingGraphs of Exponential Functions Find the exponential function f(x) = ax whose graph is given. Since f(3) = a3 = 1/8 , we see that the base is ½ . SO... f (x) = (½)x
  • 8.
  • 9.
    Speaking of Infinity… Make an infinity symbol with your right hand out in front of you. and stop your finger on the far right side of the infinity sign. Lift your left hand to be at the far left side of the infinity sign. Now move your hands at the same time and the same pace in the same direction to continue your infinity sign. Your hands should cross the middle at the same time. This one seems easy at first. Then you try to do it when your hands are doing the infinity signs in different directions. You should look like a choir director if you are doing it correctly. 
  • 10.
    We can graph Exponential Functionsusing transformations. Find the parent function f(x) = 2x in the front of your book.
  • 11.
    Ex4—Transformations Use thegraph of f(x) = 2x to sketch the graph of the function. g(x) = 1 + 2x Notice that the line y = 1 is now a horizontal asymptote.
  • 12.
    Ex5 - Usethe graph of f(x) = 2x to sketch the graph of the function. h(x) = –2x
  • 13.
    EX 6: Usethe graph of f(x) = 2x to sketch the graph of the function. k(x) = 2x –1
  • 14.
    You have finishedyour Homework!! Great job! Now go get a cookie for yourself! ;)