Find the arclength of the curve:

$\displaystyle r(t) = <6t^2, 2sqrt(6)t, ln(t)>$ when

t is less than or equal to 2, but greater than or equal to 1.

I know that the arc length formula is the integral of the magnitude of the derivative of the function r, but I don't know how to integrate it to find the arc length.

Thank you!