Question

write the first 5 terms of the sequence whose general term an

Answer 1

We will have that the first 5 terms of the sequence are:

$a_1=(-1)^1(9\cdot1)\Rightarrow a_1=-9$$a_2=(-1)^2(9\cdot2)\Rightarrow a_2=18$$a_3=(-1)^3(9\cdot3)\Rightarrow a_3=-27$$a_4=(-1)^4(9\cdot4)\Rightarrow a_4=36$$a_5=(-1)^5(9\cdot5)\Rightarrow a_5=-45$

So, the first five terms of the sequence are: -9, 18, -27, 36 & -45.