Using Logarithms to Determine Relationships This unit from the
Continuing Mathematics Project goes into detail on how
logarithms can be used to determine the laws which connect two
variables on which experimental data has been collected. The
unit follows naturally from the unit entitled The Theory of
Logarithms. The objectives of the unit are that students: (i)
understand the meanings of the terms exponential growth and
decay, as they are used in relation to natural phenomena; (ii)
perceive that money invested at 'compound interest' also grows
exponentially in denominational terms (even if it decays
exponentially in purchasing power); (iii) be able, when the
relationship between two variables x and y is of the form y =
C.ax, to plot values of log y against values of x on ordinary
graph paper, or to plot values of y against values of x on log-
linear graph paper, and so determine the constants C and a; (iv)
be able, when the relationship between two variables x and y is
of the form y = C.xa , to plot values of