 In this video, we provide the solution to question number one for the practice exam number two for math 1220, in which case we're given an integral the integral of the square root of x squared minus 25 over x dx and we're asked which trigonometric substitution will allow us to calculate this integral. So looking at the square root. This indicates we probably want to do a trigonometric integral notice we have a difference of squares where the x squared shows up first the variable shows up first in the constant shows up second. So since the variable squared minus the constant squared is the form we have this looks like a secant substitution. And since we have a 25 which is five squared, this is going to lead to the correct response being C x equals five secant theta that would be the best trigonometric substitution to use.