The book now says:
The first moment about an axis a is
µa = ( x - a ) ƒ(x) dx , (10.1)
where µ is a moment with the subscript a denoting the axis. When a = 0, µ' is the mean. The second moment about the mean is
= ( x
- a )2 ƒ(x) dx .
This is wrong.
The correct equation is:
= ( x - µ' )2 ƒ(x) dx
On page 177, Equation 10.4 did not come out right. It should be: