Question

Could someone help me with this....strange question?

Answer 1

@mathmale

Answer 2

What's the equation for the volume of a cylinder?

Answer 3

pir^h

Answer 4

Radius:
\[\Large {\color{red}{r}}={\color{red}{(x-1)}}\]

------------------------------------

Height:
\[\Large {\color{blue}{h}}={\color{blue}{(x+1)}}\]

------------------------------------

Volume

\[\Large V = \pi*r^2*h\]

\[\Large V = \pi*{\color{red}{r}}^2*{\color{blue}{h}}\]

\[\Large V = \pi*{\color{red}{(x-1)}}^2*{\color{blue}{(x+1)}}\]

I'll let you simplify

Answer 5

Better check that formula. You're getting there, but there's a significant omission in your formula.

Answer 6

pi*r^2*h
Replace with what's given!
pi * (x-1)^2 * (x+1)
Distribute (x-1)^2 and you get:
\[x^2-2x+1\]
Now you have to multiply it times (x+1): \[(x^2-2x+1)*(x+1)\] is what?

Answer 7

hang on

Answer 8

x^3-x^2-x+1

Answer 9

`x^3-x^2-x+1` is correct

so you'll have

\[\Large V = (x^3-x^2-x+1)\pi\]

or

\[\Large V = \pi(x^3-x^2-x+1)\]