Practice On Your Own Evaluate the following indefinite integrals using integration by substitution. Record u and du for each example, even if you ultimately use guess-and-check to solve the problem. 1 . 1 + 23 dr 1 = du =\farccos(r) 3. du =cos(In(r) ) 4. 1 = du=\f6. (1 + arctan(x) )6 1 + x2 U = du =