Answer: the answer is 224cm3
f(x)=lnx
y=f(x)
dy/dx= 1/x
tangent at (x,y) has slope 1/x
eqn of tangent is y = mx + c
since the tangent passes through origin, c=0
substitute y = lnx and m= 1/x to above eqn
lnx = 1
x=e
y=lne=1
Four people read 6to 8 books.
1. x - y
2. xy
3. y / x
4. x+y
5. y= x-6
6. 6x =y
7. y-x
8. x/y
9. x+y= 6
10. xy= 6