*Logarithms

Let a is an arbitrary positive real number except 0. If a^x = y, then log_ay = x

Conversely, the antilogarithm of x is the number y i.e. y = antilog_ax.

Here a^x = y is called arbitrary exponential function and log_a y = x is read is log of y to the base a is equal to x. If a = 10, log is called common & if it is e, then called natural.