Question

How do you evaluate the definite integral `int dx/x` from `[1,2]`?

Answer 1

`int_1^2(dx)/x=ln2`

Explanation:

As `d/(dx)lnx=1/x`

`int_1^2(dx)/x=int_1^2(dx)/x=[lnx]_1^2`

= `ln2-ln1=ln2-0=ln2`