Evaluate $a^3 - \dfrac{1}{a^3}$ if $a - \dfrac{1}{a} = 0$.
If given a - 1/a = 0
then a = 1/a
Sub this into the first equation
a^3 - 1/a^3 = (1/a)^3 - 1/(a^3) = 1/a^3 - 1/a^3 = 0
Did I miss something here??
+37159 
