Logarithms

1
Logarithms

• Using logarithm notation

2
Activity 1
Time allowed 2 minutes
Write the following as x .
Y 3x Y x2 Y sin x Y 2x
We need to have a way of writing the inverse of
this..
3
Logarithmic notation
2x 8
23 8
What is the value of x?
The index, 3, is known as the logarithm of 8 to
base 2.
We could write this as log28 3.
Write the following exponentials in log form
26 64 81 34 54 625 Y 2x
Log264 6 Log381 4 Log5625 4 x log2y
4
Generalising
If a number is expressed in exponential form as y
ax, then index x is known as logay
5
Log properties
Investigate the following
6
Activity 1
Time allowed rest of lesson
Turn to page 107 of your core 2 book and answer
questions in Exercise B.