Demostrar las siguientes Integraciones: 1. sen2 x . dx
= x - sen 2x + c . 2 4
(½ - ½ cos 2x) dx = ½ dx - ½ . ½cos 2x . dx = x - ¼ sen 2x = x - sen 2x + c . 2 4 2. sen4 x . dx = 3x - sen 2x + sen 4x + c . 8 4 32 sen2 x . sen2 x dx = (½ - ½ cos 2x)2 dx = {(½)2 - 2(½)(½) cos 2x + [(½) cos 2x]2} dx {¼ - ½ cos 2x + ¼ cos2 2x} dx ¼ dx - ½cos 2x dx + ¼ cos2 2x dx ¼ dx - ½.½cos 2x .(2)dx + ¼ [½ + ½ cos 2(2x)] dx ¼ dx - ¼ cos 2x .(2)dx + ¼ [½ + ½ cos 4x] dx ¼ dx - ¼ cos 2x .(2)dx + ¼.½dx + ¼.½cos 4x dx ¼ dx - ¼ cos 2x .(2)dx + ¼.½dx + ¼.½.¼ cos 4x .(4)dx ¼ dx - ¼ cos 2x .(2)dx + ⅛ dx + 1/32cos 4x .(4)dx ¼ x - ¼ sen 2x + ⅛ x + 1/32 sen 4x = ¼ x + ⅛ x - ¼ sen 2x + 1/32 sen 4x = 2/8 x + ⅛ x - ¼ sen 2x + 1/32 sen 4x = ⅜ x - ¼ sen 2x + 1/32 sen 4x + c . 3. cos4 x dx = 3x + sen 2x + sen 4x + c . 8 4 32 cos2 x. cos2 x dx = [½ + ½ cos 2x]2 dx dx =
{(½)2 + 2(½)(½) cos 2x + [(½) cos 2x]2} dx {¼ + ½ cos 2x + ¼ cos2 2x} dx ¼ dx + ½cos 2x dx + ¼ cos2 2x dx ¼ dx + ½.½cos 2x (2)dx + ¼ [½ + ½ cos 2(2)x] dx ¼ dx + ¼ cos 2x (2)dx + ¼ [½ + ½ cos 4x] dx ¼ dx + ¼ cos 2x (2)dx + ¼.½dx + ¼.½cos 4x dx ¼ dx + ¼ cos 2x (2)dx + ⅛ dx + ¼.½.¼ cos 4x (4)dx ¼ dx + ¼ cos 2x (2)dx + ⅛ dx + 1/32cos 4x (4)dx ¼ x + ¼ sen 2x + ⅛ x + 1/32 sen 4x = ¼ x + ⅛ x + ¼ sen 2x + 1/32 sen 4x = 2/8 x + ⅛ x + ¼ sen 2x + 1/32 sen 4x = 3/8 x + ¼ sen 2x + 1/32 sen 4x + c . 4. sen6 x dx
= 5x - sen 2x + sen3 2x + 3sen 4x + c . 16 4 48 64
sen2 x . sen2 x . sen2 x dx
= (sen2 x)3dx =
[½ - ½ cos 2x]3 dx
{(½)3 - 3.(½)2. ½ cos 2x + 3(½). (½ cos 2x)2 - (½ cos 2x)3} dx
(⅛ - ⅜cos 2x + 3(½).(¼)cos2 2x - ⅛cos3 2x) dx
(⅛ - ⅜cos 2x + ⅜cos2 2x - ⅛cos3 2x) dx
{⅛ - ⅜cos 2x + ⅜[½ + ½ cos (2)2x] - ⅛.cos2 2x. cos 2x} dx
{⅛ - ⅜ cos 2x + 3/16 + 3/16cos 4x - ⅛.[(1 - sen2 2x). cos 2x]} dx
{⅛ + 3/16- ⅜ cos 2x +3/16 cos 4x - ⅛[cos 2x - sen2 2x.cos 2x]}dx
{2/16 + 3/16 - ⅜ cos 2x + 3/16 cos 4x - ⅛cos 2x + ⅛sen2 2x.cos 2x}dx
{5/16- ⅜ cos 2x - ⅛cos 2x + 3/16 cos 4x + ⅛(sen 2x)2.cos2x}dx
{5/16 - 4/8 cos 2x + 3/16 cos 4x + ⅛(sen 2x)2.cos2x}dx
{5/16 - ½ cos 2x + 3/16 cos 4x + ⅛(sen 2x)2.cos2x}dx
5/16dx - ½ cos 2x .(2)dx + 3/16 cos 4x .(4)dx + ⅛(sen2x)2.cos2x dx 5/16dx - ½.½ cos 2x .(2)dx + 3/16.¼ cos 4x .(4)dx + ⅛.½(sen2x)2.(2)cos2xdx 5/16dx - ¼ cos 2x .(2)dx + 3/64cos 4x .(4)dx + 1/16(sen2x)2.(2)cos2xdx 5/16 x - ¼ sen 2x + 3/64 sen 4x + 1/16(sen 2x) 3
= 3
5/16 x - ¼ sen 2x + 3/64 sen 4x + 1/48 (sen3 2x) =
5x - sen 2x + sen3 2x + 3sen 4x + c . 16 4 48 64
5. cos6 x dx
= 5x + sen 2x - sen3 2x + 3sen 4x + c . 16 4 48 64
cos2 x. cos2 x. cos2 x dx
= (cos2 x)3 dx = [½ + ½ cos 2x]3 dx
(⅛ + 3.¼.½ cos 2x + 3(½).(½)2.cos2 2x + ⅛cos3 2x) dx
(⅛ + ⅜cos 2x + 3(½).(¼)cos2 2x + ⅛cos3 2x) dx
(⅛ + ⅜cos 2x + ⅜ cos2 2x + ⅛cos3 2x) dx
{⅛ + ⅜cos 2x + ⅜[½ + ½ cos (2)2x] + ⅛.cos2 2x. cos 2x} dx
{⅛ + ⅜ cos 2x + 3/16 + 3/16cos 4x + ⅛[(1 - sen2 2x).cos 2x]} dx
{⅛ + 3/16+ ⅜ cos 2x+3/16cos 4x + ⅛[cos 2x - sen2 2x.cos 2x]}dx
{2/16 + 3/16 + ⅜cos 2x + 3/16 cos 4x + ⅛cos 2x - ⅛sen2 2x.cos 2x}dx
{5/16 + ⅜ cos 2x + ⅛cos 2x + 3/16 cos 4x - ⅛(sen 2x)2.cos2x}dx
{5/16 + 4/8 cos 2x + 3/16 cos 4x - ⅛(sen 2x)2.cos2x}dx
{5/16 + ½ cos 2x + 3/16 cos 4x - ⅛(sen 2x)2.cos2x}dx
5/16dx + ½cos 2x .(2)dx + 3/16cos 4x .(4)dx - ⅛(sen2x)2.cos2x dx 5/16dx + ½.½ cos 2x.(2)dx + 3/16.¼ cos 4x .(4)dx- ⅛.½(sen2x)2.(2)cos2xdx 5/16dx + ¼ cos 2x .(2)dx + 3/64 cos 4x .(4)dx - 1/16(sen2x)2.(2)cos2xdx 5/16 x + ¼ sen 2x + 3/64 sen 4x - 1/16(sen 2x)2+1
= 2+1
5/16 x + ¼ sen 2x + 3/64 sen 4x - 1/16 (sen 2x)3 = 3
5x + sen 2x - sen3 2x + 3sen 4x + c . 16 4 48 64
6. sen2 ax dx
= x - sen 2ax + c . 2 4a .
[½ - ½ cos 2ax]dx = ½ dx - ½ cos 2ax]dx =
½ dx - ½.1/2a cos 2ax . (2a)]dx = ½ x - 1/4a .sen 2ax = x - sen 2ax + c .
2 4a 7. sen2x/2. cos2x/2 dx
= x - sen 2x + c . 8 16
[½ - ½ cos 2(x/2)].[½ + ½ cos 2(x/2)]dx .Simplificando:
[½ - ½ cos x].[½ + ½ cos x]dx. Tenemos una diferencia de cuadrados.
{[½]2 - [½ cos x]2} dx = {[¼] - [¼ cos2 x]} dx = ¼dx - ¼ cos2 x dx = ¼dx - ¼
{
[½ + ½ cos 2x] dx}
¼dx - ¼.½ dx - ¼.½ cos 2x dx = ¼dx - ⅛ dx - ⅛ cos 2x dx ¼dx - ⅛ dx - ⅛.(½) cos 2x .(2) dx = ¼dx - ⅛ dx - 1/16 cos 2x .(2) dx ¼ x - ⅛ x - 1/16 sen 2x = 2/8 x - ⅛ x - 1/16 sen 2x = 1/8 x - 1/16 sen 2x = x - sen 2x + c . 8 16 8. sen4 ax dx sen2 ax . sen2 ax dx= sen2 ax . sen2 ax dx = [½ - ½ cos 2ax]2dx
{¼ - ½ cos 2ax + ¼ cos2 2ax} dx
¼ dx - ½cos 2ax dx + ¼ cos2 2ax dx
¼ dx - ½.½acos 2ax (2a)dx + ¼ [½ + ½ cos 2(2ax)] dx ¼ dx - ¼acos 2ax (2a)dx + ¼ [½ + ½ cos 4ax] dx ¼ dx - ¼acos 2ax (2a)dx + ¼.½dx + ¼.½cos 4ax dx ¼ dx - ¼acos 2ax (2a)dx + ¼.½dx + ¼.½.¼acos 4ax
(4a)dx
¼ dx - ¼acos 2ax (2a)dx + ⅛ dx + 1/32acos 4ax (4a)dx
¼ x - ¼a sen 2ax + ⅛ x + 1/32a sen 4ax =
¼ x + ⅛ x - ¼a sen 2ax + 1/32a sen 4ax =
2/8 x + ⅛ x - ¼a sen 2ax + 1/32a sen 4ax =
⅜ x - ¼a sen 2ax + 1/32a sen 4ax =
⅜ x - sen 2ax + sen 4ax + c . 4a 32a . 9. sen2 2x .cos4 2x dx
sen2 2x .cos4 2x . cos2 2x dx
[½ - ½ cos 2(2x)]. [½ + ½ cos 2(2x)]. cos2 2x dx
[½ - ½ cos 4x]. [½ + ½ cos 4x]. cos2 2x dx
[¼ - ¼ cos2 4x].cos2 2x dx
[¼ .cos2 2x - ¼.cos2 2x .cos2 4x] dx
{¼[½ + ½ cos 4x] - ¼ cos2 2x + ¼ sen2 4x.cos2 2x} . dx
{⅛ + ⅛ cos 4x - ¼ [½ +½ cos 2(2)x] + ¼ sen2 4x[½ +½ cos 2(2)x]}.dx
{⅛ +⅛ cos 4x -¼ [½ + ½ cos 4x]+ ¼ sen2 4x[½ +½ cos 4x]}.dx
{⅛+⅛ cos 4x-⅛-⅛ cos 4x+⅛ sen2 4x + ⅛ sen2 4x.cos 4x]}.dx
{⅛+⅛cos 4x-⅛-⅛ cos 4x+⅛ sen2 4x + ⅛ sen2 4x.cos
4x]}.dx
[⅛ sen2 4x + ⅛ sen2 4x.cos 4x].dx
⅛ [½ -½ cos 2(4)x]dx + ⅛ (sen 4x)2.cos 4x.dx ⅛ [½ -½ cos 8x]dx + ⅛.¼ (sen 4x)2 .cos 4x.(4)dx
⅛ .½ dx - ⅛.½cos 8x dx + 1/32(sen 4x)2 .cos 4x.(4)dx
1/16dx - 1/16.⅛ cos 8x .(8)dx + 1/32 (sen 4x)2 .cos 4x.(4)dx
1/16x - 1/128 sen 8x + 1/32 (sen 4x)2+1 = 2+1 x - sen 8x + (sen 4x) 3 = x + (sen 4x)3 - sen 8x = 16 128 32(3) 16 96 128 x + sen 3 4x - sen 8x + c . 16 96 128 10. (2 - sen θ)2 dθ = 9 θ + 4cos θ + sen 2 θ + c . 2 4 [4 - 2.2.sen θ + (sen θ)2] dθ = [4 - 4sen θ + sen2 θ] dθ =
{8/2 + ½ - 4sen θ + ½ cos 2θ]}dθ = {9/2- 4sen θ + ½ cos 2θ]}dθ
9/2 dθ- 4sen θ .dθ + ½ cos 2θ .dθ =
9/2 dθ- 4sen θ .dθ + ½.½ cos 2θ .(2)dθ =
9/2 θ- 4(- cosθ) + ¼ (sen 2θ) = 9/2 θ+ 4cosθ + ¼ (sen 2θ)
9
θ + 4cos θ + sen 2 θ + c . 2 4
11. [sen2 Ф + cos Ф]2 dФ
=
[(sen2 Ф)2 + 2.(sen2 Ф).cos Ф + cos2 Ф]2 dФ =
[(½ - ½ cos 2Ф)2 + 2.(sen2 Ф).cos Ф + (½ + ½ cos 2Ф)] dФ
=
[(¼ - 2.½. ½ cos 2Ф + (½ cos 2Ф)2 + 2(sen2 Ф).cos Ф + ½ + ½ cos 2Ф]d Ф =
[(¼ - ½ cos 2Ф + ¼ cos2 2Ф + 2sen2 Ф.cos Ф + ½ + ½ cos 2Ф]d
Ф =
[(¼ - ½ cos 2Ф + ¼ cos2 2Ф + 2sen2 Ф.cos Ф + ½ + ½ cos 2Ф]d
Ф =
[(¼ + ½ + ¼ cos2 2Ф + 2sen2 Ф.cos Ф]d Ф
=
[(¼ + ½ + ¼ (½ + ½ cos 2(2Ф) + 2sen2 Ф.cos Ф]d Ф
=
[(¼ + ½ + ⅛ + ⅛ cos 4Ф + 2sen2 Ф.cos Ф]d Ф =
[(2/8 + 4/8 + ⅛ + ⅛ cos 4Ф + 2sen2 Ф.cos Ф]d Ф =
[(7/8+ ⅛ cos 4Ф + 2sen2 Ф.cos Ф]d Ф =
7/8 dФ + ⅛.¼ cos 4Ф .(4Ф).d Ф + 2 (sen Ф)2.cos Ф.d Ф = 7/8 Ф + 1/32 sen 4Ф + 2 ( sen Ф ) 2+1 = 2+1 7 Ф + sen 4 Ф + 2(sen Ф ) 3 = 7 Ф + 2sen Ф3 + sen 4 Ф + c . 8 32 3 8 3 32
12. sen 2x cos 4x dx = cos 2x - cos 6x + c . 4 12
Por Trigonometría: sen 2x cos 4x = ½ sen[2+4]x + ½ sen[2-4]x
sen 2x cos 4x = ½ sen 6x + ½ sen[-2]x
{½ sen 6x + ½ sen[-2]x}dx = {½ sen 6x - ½ sen 2x}dx
½ sen 6x .dx - ½ sen 2x .dx =½.1/6 sen 6x.(6)dx - ½.½sen 2x .(2)dx
1/12 (- cos 6x) - ¼ (- cos 2x) = - cos 6x + cos 2x =
12 4
cos 2x - cos 6x + c .
4 12
13. sen 3x sen 2x dx = sen x - sen 5x + c . 2 10
Por Trigonometría: sen 3x sen 2x = -½ cos[3+2]x + ½ cos[3-2]x
sen 3x sen 2x = -½ cos 5x + ½ cos x
[-½ cos 5x + ½ cos x] dx = -½ cos 5x . dx + ½ cos x . dx =
-½.(1/5) cos 5x .(5) dx + ½ cos x .dx = -(1/10) sen 5x + ½ sen x =
2 10
14. cos 4x cos 3x dx
Por Trigonometría: cos 4x cos 3x = ½ cos[4+3]x + ½ cos[4-3]x
cos 4x cos 3x = ½ cos 7x + ½ cos x
(½ cos 7x + ½ cos x) dx = ½ cos 7x dx + ½ cos x dx
½.(1/7) cos 7x .(7)dx + ½ cos x dx
1/14(sen 7x) + ½ (sen x) = sen 7x + sen x = sen x + sen 7x + c
14 2 14 2 15. cos2 ax dx
=
[ ½ + ½ cos 2(ax) ]dx = [ ½ + ½ cos 2ax ]dx =
½ dx + ½ .1/2acos 2ax .(2a) ]dx =
x/2 + 1/4a sen 2ax = x/2 + sen 2ax /4a + c .
16. cos4 ax dx =
cos2 ax . cos2 ax .dx
= [ ½ + ½ cos 2ax] [½ + ½ cos 2ax] dx =
[½ + ½ cos 2ax]2 dx
= [¼ + 2.½.½ cos 2ax + ¼ cos2 2ax]dx =
{¼ + ½ cos 2ax + ¼ [½ + ½ cos 2(2ax)]}dx =
{¼ + ½ cos 2ax + ⅛ + ⅛ cos 4ax}dx .Haciendo operaciones:
{⅜ + ½ cos 2ax + ⅛ cos 4ax}dx
⅜ dx + ½ .1/2acos 2ax .(2a) dx + ⅛.
¼
a cos 4ax .(4a)}dx 3x/8 + 1/4a sen 2ax + 1/32a sen4ax + c .17. sen2 ax . cos2 ax .dx =
[ ½ - ½ cos 2(ax)] [½ + ½ cos 2(ax)] dx =
[(½)2 - (½ cos 2ax)2] dx
= [¼ - ¼ [½ + ½ cos 2(2ax)2] dx =
[¼ - ⅛ - ⅛ cos 4ax] dx = [2/8 - ⅛ - ⅛ cos 4ax] dx =
[⅛ - ⅛ cos 4ax] dx = ⅛dx - ⅛.¼a cos 4ax.(4a)] dx =
x/8 - 1/32a .sen 4ax = x/8 - sen 4ax/32a + c .
18. sen4/2 cos2/2 .d =
sen2/2.cos2/2.sen2/2 d
= (sen /2 .cos /2)2 .sen2/2 d=
Por Trigonometría:sen 2x = 2senx.cosx ; sen /2 .cos /2 = sen(2./2) sen /2 .cos /2= ½ sen .
(sen /2 .cos /2)2 .sen2/2 d=
(½sen. sen 2/2) d
= {(½sen [½ - ½ cos (2./2)]} d=
[½sen ( ½ - ½ cos )] d= [¼ sen - ¼ sen .cos ] d=
¼ sen d - ¼ (sen )1.cos d .
v = sen El diferencial esta completo, se procede a integrar.
dv = cos d Se usa: vn dv = v n+1 + c . n = 1 n+1 ¼ (- cos ) - ¼ .sen 2 = - cos - sen 2 + c . 2 4 8 19. csc ax 4 . dx = cot ax
1 .
Por Trigonometría: csc ax = sen ax = 1 = sec ax
cot ax cos ax cos ax . sen ax
csc ax 4.dx
= (sec ax)4.dx = sec4 ax.dx =sec2 ax. sec2 ax dx = cot ax
(1 + tg2 ax). sec2 ax . dx
= (sec2 ax + tg2 ax . sec2 ax). dx =
sec2 ax . dx + tg2 ax . sec2 ax). dx =
sec2 ax . dx + (tg ax)2 . sec2 ax. dx =
v = ax 1 ra integral : Falta (a) para completar el diferencial.
dv = a dx Se aplica: sec2 v = tg v + c .
v = tg ax 2 da integral : Falta (a) para completar el diferencial.
dv = a.sec2 ax dx Se aplica: vn dv = v n+1 + c .
n+1 . 1 .sec2 ax .(a) dx + . 1 . (tg ax)2 .(a) sec2 ax. dx
= a a tg ax + (tg ax)2+1 = tg ax + (tg ax)2+1 + c . a (2+1)a a 3a 20. sen2 x . cos6 x . dx .
sen2 x . cos2 x . cos2 x . cos2 x . dx .
(sen x . cos x)2 .(cos x . cos x)2 . dx .
Por trigonometría: sen x.cos x = sen 2x ;
cos2 x
= cos 2x + 1 = ½ cos 2x + ½ .Sustituyendo en la integral .
2
(sen x . cos x)2 .(cos x . cos x)2 . dx .
( ½ sen 2x)2 .( ½ cos 2x + ½)2 . dx .
(½ sen 2x)2 .( ½ cos 2x + ½)2 . dx .Haciendo operaciones. (1/4 sen2 2x) .[1/4 cos2 2x + 2. ½ cos 2x . ½ + ¼] . dx .
(1/4 sen2 2x) .[1/4 cos2 2x + ½ cos 2x + ¼] . dx .
[1/16 sen2 2x . cos2 2x + 1/8 sen2 2x . cos 2x + 1/16 sen2 2x].dx .
1/16 sen2 2x . cos2 2x + 1/8 . ½ (sen 2x)2.cos 2x.(2)+ 1/16sen2 2x.dx .
1/16sen2 2x.cos2 2x +1/16 (sen 2x)2.cos 2x.(2)+ 1/16[1/2 - ½ cos 2(2x) ] .dx . 1/16(sen 2x .cos 2x)2 dx + ( sen 2x)2+1 + 1/16.1/2 dx - 1/16 . ½ .1/4 cos 4x .(4)dx .
16(2+1)
1/16[1/2sen 2(2x)]2 dx + ( sen 3 2x) + 1/32 x - 1/128 cos 4x .(4)dx .
16(3)
1/16[1/4sen2 4x)]dx + ( sen 3 2x) + 1/32 x - 1/128 sen 4x .
48
1/16 . 1/4 [sen2 4x].dx + ( sen 3 2x) + 1/32 x - 1/128 sen 4x .
48
1/16 . 1/4 [1/2 – ½ cos 2(4x)]dx + ( sen 3 2x) + 1/32 x - 1/128 sen 4x .
48
1/64 [1/2 – ½ cos 8x]dx + ( sen 3 2x) + 1/32 x - 1/128 sen 4x .
48
1/64 . 1/2 dx – 1/64 . ½ cos 8x dx + ( sen 2x) + 1/32 3 x - 1/128 sen 4x .
48
1/128 x – 1/128 . 1/8 cos 8x . (8)dx + ( sen 3 2x) + 1/32 x - 1/128 sen 4x .
48
5/128 x - 1/1024 sen 8x + (sen3 2x) - 1/128 sen 4x + c .
48
21. (1 + cos x)3 . dx .
(13 + 3.12.cos x + 3.1.cos2 x + cos3 x) . dx .
(1 + 3cos x + 3cos2 x + cos3 x) . dx .
[1 + 3cos x + 3(½ + ½ cos 2x) + cos2 x .cos x] . dx .
[1 + 3cos x + 3(½ + ½ cos 2x) + (1 - sen2 x) .cos x] . dx .
[2/2 + 3cos x + 3/2 + 3/2 cos 2x + cos x - sen2 x .cos x] . dx .
[5/2 + 4cos x + 3/2 cos 2x - sen2 x .cos x] . dx .
5/2 dx + 4 cos x dx + 3/2 . ½ cos 2x .(2) dx - (sen x)2 .cos x . dx .
2+1 5x + 4 sen x + 3sen 2x - (sen x)3 + c . 2 4 3
22. (√sen 2θ - cos 2θ)2 dθ
[√sen 2θ )2 - 2(√sen 2θ ) . cos 2θ + cos22θ ] dθ
[sen 2θ - 2(sen 2θ )1/2 . cos 2θ + cos22θ ] dθ
{sen 2θ - 2(sen 2θ )1/2 . cos 2θ + [1/2 + ½ cos 2(2θ)]} dθ
{sen 2θ - 2(sen 2θ )1/2 . cos 2θ + 1/2 + ½ cos 4θ} dθ
sen 2θ . dθ - 2.½ (sen 2θ )1/2.cos 2θ.(2) + 1/2dθ + ½ .1/4 cos 4θ.(4) dθ
½ sen 2θ.(2). dθ - (sen 2 θ ) 1/2+1 + θ/2 + 1/8 sen 4θ dθ
½+1
½ (- cos 2θ) - (sen 2 θ ) 1/2+1 + θ/2 + 1/8 sen 4θ dθ
½+1
- ½ (cos 2θ) - (sen 2 θ ) 3/2 + θ/2 + 1/8 sen 4θ dθ
3/2
- ½ (cos 2θ) - 2(sen 2 θ ) 3/2 + θ/2 + 1/8 sen 4θ + c . 3
Ordenando:
θ/2 + 1/8 sen 4θ- 2(sen 2 θ ) 3/2 - ½ (cos 2θ) + c .
3 23. (√cos θ - 2sen θ)2 dθ
[(√cos θ )2 - 2 (√cos θ .2sen θ + (2 sen θ)2 ] dθ
[(cos θ ) - 2.2 (cos θ)1/2.sen θ + (4 sen2 θ)] dθ
[cos θ - 4(cos θ)1/2.sen θ + 4(1/2 - 1/2 cos 2θ] dθ
[(cos θ ) - 4(cos θ)1/2.sen θ + 4/2 - 4/2 cos 2θ] dθ
[cos θ - 4(cos θ)1/2.sen θ + 2 - 2 cos 2θ] dθ
(cos θ ) dθ - 4(cos θ)1/2.sen θ dθ + 2dθ - 2.½ cos 2θ.(2) .dθ
sen θ - 4 ( cos θ ) 1/2+1 + 2θ - sen 2θ ½+1
sen θ - 4 ( cos θ ) 3/2 + 2θ - sen 2θ + c . 3/2
sen θ - 8 ( cos θ ) 3/2 + 2θ - sen 2θ + c . 3
24. (sen 2x - sen 3x)2 dx
(sen2 2x - 2 sen 2x .sen 3x + sen2 3x)dx
{(½ - ½ cos 2(2x) - 2[- ½ cos(2+3)x + ½ cos(2-3)x] + [½ - ½ cos 2(3x)]dx
{(½ - ½ cos 4x) - 2[- ½ cos 5x + ½ cos (-x)] + [½ - ½ cos 6x]}dx
{½ - ½ cos 4x + cos 5x - cos (-x) + ½ - ½ cos 6x}dx Por Trigonometría: cos (-x) = cos (x) .
{½ + ½ - ½ cos 4x + cos 5x + cos x - ½ cos 6x}dx
{1 - ½ cos 4x + cos 5x + cos x - ½ cos 6x}dx
dx - ½.1/4 cos 4x .(4) dx + 1/5 cos 5x .(5)dx + cos x.dx - ½ .1/6 cos 6x .(6)dx
x dx -1/8 cos 4x .(4) dx + 1/5 cos 5x .(5)dx + cos x.dx - 1/12 cos 6x .(6)dx
x -1/8 sen 4x + 1/5 sen 5x + sen x - 1/12 sen 6x . x - sen 4x + sen 5x + sen x - sen 6x + c .
8 5 12 25. (sen x + cos 2x)2 dx
(sen2 x + 2 sen x .cos 2x + cos2 2x) dx
Por Trigonometría: cos 2x = cos2x – sen2x ; sen2x = ½-½cos 2x ; cos2x = ½+½ cos 2x.
[(½ - ½ cos 2x) + 2 sen x (cos2x - sen2x) + ½ + ½ cos 2(2x)] dx
[½ - ½ cos 2x + 2 cos2 x .sen x - 2sen2 x. senx + ½ + ½ cos 4x] dx
[½ + ½ - ½ cos 2x + 2 cos2 x .sen x - 2sen2 x. senx + ½ cos 4x] dx
[1 - ½ cos 2x + 2 cos2 x .sen x - 2(1 - cos2x).senx + ½ cos 4x] dx
[1 - ½ cos 2x + 2 cos2 x .sen x - 2 sen x + 2cos2 x.senx + ½ cos 4x] dx
[1 - ½ cos 2x + 4 cos2 x .sen x - 2 sen x + ½ cos 4x] dx .
dx - ½ . ½ cos 2x .(2)dx + (-)4(cosx)2 .(-)sen x dx - 2 sen x .dx + ½.1/4
cos 4x.(4) dx
dx -1/4cos 2x .(2)dx - 4(cosx)2.(-)sen x dx -2sen x .dx + 1/8cos 4x.(4) dx x-sen 2x -4(cos x)3-2 (- cos x)+ sen 4x + c .
4 3 8 x-sen 2x -4(cos x)3+ 2 cos x+ sen 4x + c .
4 3 8
26. (cos x + 2cos 2x)2 dx
[(cos x)2 + 2(cos x).(2cos 2x) + (2 cos 2x)2 dx
(cos2 x + 4 cos x .cos 2x + 4cos2 2x) dx
(½ + ½ cos 2x + 4 cos x .(cos2 x - sen2 x) + 4(½ + ½ cos 2(2x) dx
½ + 2 + ½ cos 2x + 4 cos2 x. cos x - 4sen2 x.cos x + 2 cos 4x] dx
5/2 + ½ cos 2x + 4 cos2 x. cos x - 4sen2 x.cos x + 2 cos 4x] dx
[5/2 + ½ cos 2x + 4(1 - sen2 x) . cos x - 4sen2 x.cos x + 2 cos 4x] dx
[5/2 + ½ cos 2x + 4cos x - 4sen2 x .cos x - 4sen2 x.cos x + 2 cos 4x] dx
[5/2 + ½ cos 2x + 4cos x - 8sen2 x .cos x + 2 cos 4x] dx
5/2dx + ½.½cos 2x.(2)dx + 4(-)cos x.(-)dx - 8(sen x)2 .cos x.dx + 2.1/4cos 4x.(4)dx
5/2dx + 1/4 cos 2x.(2)dx - 4 cos x.(-)dx - 8(sen x)2.cos x.dx + ½ cos 4x.(4)dx
5x + sen 2x - 4sen x – 8(sen x)2+1 + sen 4x + c .
2 4 2+1 2
5x + sen 2x - 4sen x - 8(sen x)3 + sen 4x + c . 2 4 3 2