Question

What is the explicit formula for this sequence -1,4,-16,64

Answer 1

The answer is c.

Explanation:

`a_(1) =-1*(-4)x^(n-1)`

`a_(1) =-1(-4)^(1-1)`

`a_(1) =-1(-4)^(2) \\a_(1) =-1(1)\\a_(1) =-1`
`a_(2) =-1(-4)^(2-1) \\a_(2) =-1(-4)^(1) \\a_(2) =-1(-4)\\a_(2)=4`
`a_(3)=-1(-4)^(3-1) \\a_(3)=-1(-4)^(2) \\a_(3)=-1(16)\\a_(3)=-16`