338. e sin *cos xax 339. etan * sec2xdx 340. eln x dx X eln(1-t) 341. -dt 1 - t In the following exercises, verify by differentiation that Inx dx = x (Inx - 1) + C, then use appropriate changes of variables to compute the integral. 342. fx Inxdx (Hint: / x Inxdx = = / x In (x2) dx) 343. / x2 In(x2) dx