#### Answer

$ a_1=1,a_2=1, a_3=\dfrac{1}{2}; a_4=\dfrac{1}{6}$

#### Work Step by Step

The general formula to find the nth term of a Geometric sequence is given as: $ a_{n}=a_1r^{n-1}$
In order to calculate the General formula of a Geometric sequence we will multiply the first term $ a_1$ by the product of the common ratio with itself one unit less then a Geometric sequence.
In order to calculate the first $4$ terms of the sequence we will have to plug $ n=1,2,3,4$ into the given equation.
So, we get $ a_1=1,a_2=1, a_3=\dfrac{1}{2}; a_4=\dfrac{1}{6}$