Hello, italipinogirl!

And this is what I did: .

. . How did you get2x?

Now the answer is: .

We have: .

Separate variables: .

Integrate: .

. . . . . . . .

. . . . . . . .

We have: .

Separate variables: .

Integrate: .

. . . . . . . .

. . . . . . . .

Separate variables: .

Integrate: .

Therefore: .