EXPONENTIAL AND LOGARITHMIC FUNCTIONS
EXPONENTIAL FUNCTIONIf x and b are real numbers such that b > 0 and b ≠ 1, then f(x) = bx is an exponential function with base b.Examples of exponential functions: a)   y = 3x               b)   f(x) = 6x               c) y = 2xExample: Evaluate the function y = 4xat the given values of x.                   a) x = 2               b) x = -3               c) x = 0
PROPERTIES OF EXPONENTIAL FUNCTION y = bx   The domain is the set of all real numbers.
   The range is the set of positive real numbers.
   The y – intercept of the graph is 1.
   The x – axis is an asymptote of the graph.
   The function is one – to – one. The graph of the function y = bxy1xo
EXAMPLE 1:   Graph the function y = 3xy1xo
EXAMPLE 2:   Graph the function y = (1/3)xy1xo
NATURAL EXPONENTIAL FUNCTION:  f(x) = exy1xo
LOGARITHMIC  FUNCTIONFor all positive real numbers x and b, b ≠ 1, the inverse of the exponential function y = bx is the logarithmic functiony = logbx.In symbol,     y = logb x     if and only if     x = byExamples of logarithmic functions: a)   y = log3 x       b)   f(x) = log6 x       c) y = log2 x
EXAMPLE 1:   Express in exponential form:EXAMPLE 2:   Express in logarithmic form:
PROPERTIES OF LOGARITHMIC FUNCTIONS   The domain is the set of positive real numbers.
   The range is the set of all real numbers.
   The x – intercept of the graph is 1.
   The y – axis is an asymptote of the graph.
   The function is one – to – one. The graph of the function y = logb xyxo1
EXAMPLE 1:   Graph the function y = log3 xy1xo
EXAMPLE 2:   Graph the function y = log1/3 xyx1o
PROPERTIES OF EXPONENTSIf a and b are positive real numbers, and m and n are rational numbers, then the following properties holds true:
To solve exponential equations, the following property can be used:bm = bn    if and only if   m = n   and  b > 0,  b ≠ 1EXAMPLE 1:   Simplify the following:EXAMPLE 2:   Solve for x:
PROPERTIES OF LOGARITHMSIf M, N, and b (b ≠ 1) are positive real numbers, and r is any real number, then
Since logarithmic function is continuous and one-to-one, every positive real number has a unique logarithm to the base b. Therefore,logbN = logbM          if and only if          N = M EXAMPLE 1:   Express the ff. in expanded form:
EXAMPLE2:   Express as a single logarithm:
NATURAL LOGARITHMNatural logarithms are to the base e, while common logarithms are to the base 10. The symbol  ln x  is used for natural logarithms.EXAMPLE:   Solve for x:

Math12 lesson11

  • 1.
    EXPONENTIAL ANDLOGARITHMIC FUNCTIONS
  • 2.
    EXPONENTIAL FUNCTIONIf xand b are real numbers such that b > 0 and b ≠ 1, then f(x) = bx is an exponential function with base b.Examples of exponential functions: a) y = 3x b) f(x) = 6x c) y = 2xExample: Evaluate the function y = 4xat the given values of x. a) x = 2 b) x = -3 c) x = 0
  • 3.
    PROPERTIES OF EXPONENTIALFUNCTION y = bx The domain is the set of all real numbers.
  • 4.
    The range is the set of positive real numbers.
  • 5.
    The y – intercept of the graph is 1.
  • 6.
    The x – axis is an asymptote of the graph.
  • 7.
    The function is one – to – one. The graph of the function y = bxy1xo
  • 8.
    EXAMPLE 1: Graph the function y = 3xy1xo
  • 9.
    EXAMPLE 2: Graph the function y = (1/3)xy1xo
  • 10.
  • 11.
    LOGARITHMIC FUNCTIONForall positive real numbers x and b, b ≠ 1, the inverse of the exponential function y = bx is the logarithmic functiony = logbx.In symbol, y = logb x if and only if x = byExamples of logarithmic functions: a) y = log3 x b) f(x) = log6 x c) y = log2 x
  • 12.
    EXAMPLE 1: Express in exponential form:EXAMPLE 2: Express in logarithmic form:
  • 13.
    PROPERTIES OF LOGARITHMICFUNCTIONS The domain is the set of positive real numbers.
  • 14.
    The range is the set of all real numbers.
  • 15.
    The x – intercept of the graph is 1.
  • 16.
    The y – axis is an asymptote of the graph.
  • 17.
    The function is one – to – one. The graph of the function y = logb xyxo1
  • 18.
    EXAMPLE 1: Graph the function y = log3 xy1xo
  • 19.
    EXAMPLE 2: Graph the function y = log1/3 xyx1o
  • 20.
    PROPERTIES OF EXPONENTSIfa and b are positive real numbers, and m and n are rational numbers, then the following properties holds true:
  • 21.
    To solve exponentialequations, the following property can be used:bm = bn if and only if m = n and b > 0, b ≠ 1EXAMPLE 1: Simplify the following:EXAMPLE 2: Solve for x:
  • 22.
    PROPERTIES OF LOGARITHMSIfM, N, and b (b ≠ 1) are positive real numbers, and r is any real number, then
  • 23.
    Since logarithmic functionis continuous and one-to-one, every positive real number has a unique logarithm to the base b. Therefore,logbN = logbM if and only if N = M EXAMPLE 1: Express the ff. in expanded form:
  • 24.
    EXAMPLE2: Express as a single logarithm:
  • 25.
    NATURAL LOGARITHMNatural logarithmsare to the base e, while common logarithms are to the base 10. The symbol ln x is used for natural logarithms.EXAMPLE: Solve for x:

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