# Homework Help: Integration by substitution

1. Nov 11, 2011

### aub

can someone please explain to me the yellow area?

2. Nov 11, 2011

### JHamm

The first line sets up the substitution of u in place of $\log _e (z)$, the next line takes the derivative of each side and the final line rearranges for an expression for $dz$; then these can be used to change the integrand :)

3. Nov 15, 2011

### aub

ok thanks
did well on the exam btw :)

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