A-Level MathsLogarithms


Logs, short for logarithms, provide a way to refer to the powers in an expression. When you come across logs, you will see the word ‘log’ followed by a small number that we call a subscript – this subscript is known as the ‘base’. This is followed by a number on brackets although sometimes the brackets are left out.

\log_a(b)=c

Replace ‘log’ with ‘the power of’ and this reads as ‘the power of a to get a result of b is c’. So it evident that this can be used interchangeably with the equation

a^c=b

Example – \log_2(8)=3 can be changed to 2^3=x and so x is 8.

See more on logs: