One problem is where you expanded the integrand... .
Hi, here are the parameters:
26-3-3
Find volume of the equation
y = 2 - x
rotated about X axis using disk method, boundaries are y = 0 and x = 0
Formula: V = pi (int) y^2 dx
Attempt:
since y = 2 - (2) = 0, 2 is an x-coordinate boundary. So the upper and lower limits of this integral are 2 and 0. X axis intercepts. Correct?
from there:
= pi (int) (2-x)^2
(2-x)^2 = 4 - 3x
= pi (int) 4 - 3x dx
= pi/3 (int) 4 - x dx
Integration:
= pi/3 4x - 1/2(x^2)
Plugging in 2 = 6.3776
However, the answer is 8.776. Any idea where I went wrong? thanks.
Do you really need Calculus to do this? y= 2- x is a straight line. When x= 0, y= 2. When y= 0, x= 2. Rotating around the x-axis gives a cone with height 2 and radius 2. The volume of a cone of height h and radius r is given by .