Integration by Substitution

1 0:01
2 2:37
3 6:41
4 10:45
5 12:55
6 16:01
7 19:21
8 21:39
9 24:17
10 27:48
11 29:53
12 32:11
13 40:38
14 44:23
15 47:15
16 50:14
17 52:40
18 56:38
19 59:08
20 1:01:40
21 1:04:04