Singularities/Residues/Applications 731
1
(^00) xa ln x 7rba
- --b-dx = -.- 2 -(7rcosa7r -lnbsina7r), -1 <a< 0, b > O
o x + sm a7r
1.100 (lnx)2 dx = 2_71'3
0 x^2 +x+l 81v'3
- (PV) loo ~x:~ = i7r2
3.
9
1
00
(lnx) dx _ 7rlna [ 4 (ln ) 2 2 ]
· 2 2 -
8
a + 571' , a > 0
0 x +a a
1
(^00) lnxdx
- o (x + 1)2JX = -71'
- loo xdx = !71'2
0 sinhx^4
1
(^00) sinax 1 1
12. ~h dx = -7rtanh -a'lf', a real
0 smx^2 2
1
(^00) cosh 2x 1 1
- h dx=-7rsec-a7r,-l<a<l
0 cos x 2 2
1
(^00) xcosax 1
14.. h dx = -^2 2 1
4
71' sech -a'lf', a real
0 sm x^2
1
(^00) cos ax dx 1 1
- h = -
2
7rsech -
2
a7r, -1<a<1
0 cos x
-1 { s
2
16. .C (s } 1.^1
2 + 4 ) 2 = 4 sm2t+ 2 tcos2t
{
1 } 4
00
(-1r-^1 1
17 .. .c-^1 h = 1-- '°" cos -(2n - l)7rt
s cos s 7r L.J 2n - 1 2
n=l
_^1 { 1 } 1 2 2 L
00
- C (-1r
ssms^2. h = - 2 t + 7r^2 --n^2 -(1-cosn7rt)
n=l
-1 { 1 } · 8
00
(-l)n. 1
- C scoss 2 h = t + 71' 2 L (,n- 2 l) 2 sin - 2 (2n - 1 )7rt
n=l
20. .c-l { coshas } =! (t^2 + a^2 b^2 ) 16b
2
~ (-l)n
s3 coshbs 2 7r^3 ~ (2n -1)^3
(2n-l)7ra (2n-l)7rt (O b)
cos
2
b cos
2
b < a <
- = -71'
l
oo dx 1
1 x../x^2 -1 2
22. f 1 dx ~ = 5:,
-1 (1+x^2 )^2 v1-x^2 8v2
f
23.^1 -r;:==d;::x::;:==::;= -
-1 {/(1 + x)^2 (1-x)