Simplify. Write in Standard Form. r²(r+1)-r(2r²-1)
PLEASE EXPLAIN HOW YOU GOT IT

−r^3+r^2+r

Step-by-step explanation:

Let's simplify step-by-step.

r^2(r+1)−r(2r^2−1)

Distribute:

=(r^2)(r)+(r^2)(1)+−2r^3+r

=r^3+r^2+−2r^3+r

Combine Like Terms:

=r^3+r^2+−2r^3+r

=(r^3+−2r^3)+(r^2)+(r)

=−r^3+r^2+r

Step-by-step explanation:

1) If the diameter is included:

2(4)*pi/2+2(4)

4pi+8

2)If it isn't included

2(4)*pi/2

4pi