Help with Double Integrals - trying to use Fubini's Theorem

[young cypress]

Hi there,

So I'm trying to do a definite double integral, then broke it up using integral properties and Fubini's Theorem:

[young cypress]

Here's how I went about it:

,tex $\int_1^4 1/x dx$

,tex $\int_1^4 1/x dx = 2 ln(2)$

[thorny schooner]

Arsalan Zahid

[young cypress]

So I thought I could just substitute that into the original equation:

However, this changes the answer.

,tex $2 ln(2) \int_1^2 y dy = 3 ln (2)$

[thorny schooner]

Arsalan Zahid

[young cypress]

However, when I compute the integral from beforehand,