Question

If a₁ = 10 and an
=
-4an-1 then find the value of a4.

Answer 1

Explanation:

`a_(1) =10\\a_(n)=-4a_(n-1)\\put~n=2,3,4\\a_(2)=-4a{1}=-4(10)=-40\\a_(3)=-4a_(2)=-4(-40)=160\\a_(4)=-4a_(3)=-4(160)=-640`