Graph of
Logarithmic functions
Graph of y = log x             b >1
                                b




2


1

     1/b
           1   b                     b2

-1                 If x = ------ , then y   = ------

                          1/b                  -1
                            1                   0
                            b                   1
                            b2                   2
Sketch the graph of y = log |x|                b >1
                                                       b


y = log (-x) if x < 0                                              y = log x if x > 0
       b                                                                  b

                                             2


                                             1



           -b2                 -b       -1       1      b                      b2
   If x = ------ , then y = ------                   If x = ------ , then y = ------
                 -1              0                            1                     0
                 -b              1                            b                     1
                 -b2                2                         b2                    2

                          Graph of y = log |x|   b>1
                                             b
 is symmetric with respect to y-axis, that is, logb|x| is an even function.
Graph of y = log x   b<1
                    b
                          If x = ------ , then y   = ------

                                  b                    1
                                  1                    0
                                  1/b                  -1
1
                                  1/b2                 -2

          1   1/b         1/b2
      b

-1


-2
Sketch the graph of y = log |x|                    b<1
                                                            b
y = log (-x) if x < 0                                                y = log x if x > 0
        b                                                                   b

If x = ------ , then y   =   ------                         If x = ------ , then y = ------
         -1                       0                                  1                   0
         -1/b                    -1                                  1/b                -1
         -1/b2                   -2                                  1/b2               -2

         -1/b2                        -1/b -1            1 1/b                   1/b2



                                                -1



                                                -2


                             Graph of y = log |x|        b<1
                                                     b
 is symmetric with respect to y-axis, that is, logb|x| is an even function.
Graph of y = log (x+3)
                          5




            1




-3     -2       2

                    If x = ------ , then y   = ------

                              -2                  0
                               2                 1
Graph of y = log         (x-3)
                       0.5

                 If x = ------ , then y   = ------

                             4                 0
                             3.5               1
1
                 3.5



         3   4
Graph of y = -log (x+3)
                    0.5




           1


-3 -2 -1

               If x = ------ , then y   = ------

                      -2                     0
                      -1                     1

Logarithmic functions

  • 1.
  • 2.
    Graph of y= log x b >1 b 2 1 1/b 1 b b2 -1 If x = ------ , then y = ------ 1/b -1 1 0 b 1 b2 2
  • 3.
    Sketch the graphof y = log |x| b >1 b y = log (-x) if x < 0 y = log x if x > 0 b b 2 1 -b2 -b -1 1 b b2 If x = ------ , then y = ------ If x = ------ , then y = ------ -1 0 1 0 -b 1 b 1 -b2 2 b2 2 Graph of y = log |x| b>1 b is symmetric with respect to y-axis, that is, logb|x| is an even function.
  • 4.
    Graph of y= log x b<1 b If x = ------ , then y = ------ b 1 1 0 1/b -1 1 1/b2 -2 1 1/b 1/b2 b -1 -2
  • 5.
    Sketch the graphof y = log |x| b<1 b y = log (-x) if x < 0 y = log x if x > 0 b b If x = ------ , then y = ------ If x = ------ , then y = ------ -1 0 1 0 -1/b -1 1/b -1 -1/b2 -2 1/b2 -2 -1/b2 -1/b -1 1 1/b 1/b2 -1 -2 Graph of y = log |x| b<1 b is symmetric with respect to y-axis, that is, logb|x| is an even function.
  • 6.
    Graph of y= log (x+3) 5 1 -3 -2 2 If x = ------ , then y = ------ -2 0 2 1
  • 7.
    Graph of y= log (x-3) 0.5 If x = ------ , then y = ------ 4 0 3.5 1 1 3.5 3 4
  • 8.
    Graph of y= -log (x+3) 0.5 1 -3 -2 -1 If x = ------ , then y = ------ -2 0 -1 1