Question

How to solve this integral? I didn't understand what is this "x".

Answer 1

what is sen again? was it sine?

Answer 2

aah it's sin

Answer 3

ohkay it says x = 3sinu (im gonna use sin) so sub that in \[\int \frac{dx}{\sqrt{9 + (3\sin u)^2}}\]
\[\int \frac{dx}{\sqrt{9 + 9\sin^2 u}}\] got that so far?

Answer 4

now i'll factor out 9 \[\int \frac{dx}{\sqrt{9(1 + \sin^2 u)}}\]

Answer 5

do you have a question? you were typing something @jpsmarinho

Answer 6

Right, but the integral is relative to x,however, the variable is u

Answer 7

we'll worry about that later but here is a drawing....it says that the sine of u is x/1 so we can make a triangle we'll use that for references later