If a be the first term, l the nth and p the product of first n terms of a G.P. show that, `p^(2) = (al)^(n)`.

Explanation

` l = a_(n) = ar^(n-1)`
` therefore p = a .ar .ar^(2) … ar^(n-1)`
` = a^(n) .r^(1 + 2 + … + n-1)`
` = a^(n) . r ^((n-1)(n))/(2)`
` = (a .ar^(n-1))^((n)/(2))`
` = (al^((n)/(2))`