6.2 volume

Question 1

when and how to use disk method

Answer 1

y(x) given revolving around x axis aka y=something
x(y) given revolving around y axis aka x=something
V=π∫[r(x)]^2dx

Question 2

when and how to use washer method

Answer 2

same as disk, outer disk-inner disk
y(x) given around y=something
x(y) given around x=something
V=π∫([R(x)]^2–[r(x)]^2)dx

Question 3

how to do volume of solids w known cross sections

Answer 3

With known area function A(x)
V=∫A(x)dx or for y

Question 4

when and how to do shell method

Answer 4

representative rectangle of shell is parallel to axis of revolution
V=2π∫r(y)h(y)dy revolving around y=something and switch for x