Question

Write the explicit formula that represents the geometric sequence -2, 8, -32, 128

Answer 1

`a_(1)=-2 \\ \\ a_(2)=8 \\ \\ q= (a_(2))/(a_(1)) \\ \\ q= (8)/(-2)=-4 \\ \\ a_(n)=a_(1)*q^(n-1) \\ \\ a_(n)=-2*-4^(n-1)`