Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng Nguyªn hµm - tÝch ph©n vµ c¸c øng dông a.tÝnh tÝch ph©n b»ng ®Þnh nghÜa Ph−¬ng ph¸p: 1. §Ó x¸c ®Þnh nguyªn hµm cña hµm sè f(x), Chóng ta cÇn chØ ra ®−îc hµm sè F(x) sao cho: F’(x) = f(x). • ¸p dông b¶ng c¸c nguyªn hµm c¬ b¶n, c¸c hµm sè s¬ cÊp . • Neáu gaëp daïng caên thöùc ñöa veà daïng soá muõ phaân theo coâng thöùc: , ( 0) n m n mx x m= ≠ • Neáu gaëp daïng ( )nP xx thöïc hieän pheùp chia theo coâng thöùc: 1, ( ); , ( ) m m m n n n n m x xx m n m n x x x − −= > = < . • Coâng thöùc ñoåi bieán soá (loaïi 2): Tích phaân daïng: ( )( ) . '( )f g x g x dx∫ Ñaët g(x) = u => g’(x)dx = du ( ( )) '( ) ( )f g x g x dx f u du=∫ ∫ . 2. Mét sè d¹ng c¬ b¶n: 1. Sö dông c«ng thøc c¬ b¶n: 1. Daïng : ñaët u = ax + b ⇒du = adx dx=( ) ( 1, 0)ax b dx aα α+ ≠ ≠∫ ⇒ 1 dua ( ) ( ) 1!1( ) 1 ( 1) ax buax b dx u du C C a a a αα α α α α ++ ++ = = + = ++ +∫ ∫ 2. Daïng : ñaët ( ) 1 , ( 0, 1)n nax b x dx aα α−+ ≠∫ ≠ 1 1 1 1 1 1. . 1 (( ) ( 1) ( 1) nu=ax n n n n n b du a n x dx x dx du an u ax bax b x dx u du C C an na na α α α α α α − − + + − + ⇒ = ⇒ = ++ = = + =+ +∫ ∫ ) + 3. Daïng: ). cos sin ( 1) a xdxα α ≠ −∫ ( Ñaët 11cos sin ) cos sin cos ( 1) u x du xdx x xdx u du x Cα α αα +−= ⇒ = − ⇒ = − = ++∫ ∫ ). cos ( 1) sin xb xdxα α ≠ −∫ (Ñaët 11sin cos sin 1 du=cos xdx sin xu x xdx u du xα α αα += ⇒ ⇒ = = ++∫ ∫ C 4. Daïng: 1 ln ( 0)dx ax b C a ax b a = + + ≠+∫ Neáu gaëp : ( )P x ax b+ vôùi baäc : laøm baøi toaùn chia. ( ) 1P x ≥ GV: NguyÔn Thanh S¬n 1 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng 5. Daïng: 2cos ( ) dx x a btgx+∫ Ñaët 2 2 1 1 1; l cos cos ( )2 dx co s bdx dx duu a btgx du du a btgx C x x b x a btgx b u b = + ⇒ = ⇒ = = = + ++∫ ∫ n 2. Coâng thöùc: ( ) '( ) ln u u x u aa u x dx a du C a = = +∫ ∫ 3. Coâng thöùc ñoåi bieán soá (loaïi 1): Tích phaân daïng: ( )( ) . '( )f g x g x dx∫ Ñaët g(x) = u => g’(x)dx = du ( ( )) '( ) ( )f g x g x dx f u du=∫ ∫ 4. Coâng thöùc : 2 2 2 1). ln .( 0) 2 ). ln du u aa C a u a a u a dub u u k C u k α −= + ≠− + = + + ++ ∫ ∫ 5. Coâng thöùc : 2 2 2ln 2 2 x x k kx kdx x x k C++ = + + + +∫ 3. Mét sè d¹ng th−êng gÆp: 1. Tích phaân daïng: 2 2 2 21). (mx+n)dx dx (mx+n)dx 2). 3). 4). dx ax bx c ax bx c ax bx c ax bx c+ + + + + + +∫ ∫ ∫ ∫ + Tuyø vaøo moãi daïng aùp duïng caùc coâng thöùc tính tích phaân chæ trong baûng sau: Töû soá baäc nhaát Töû soá haèng soá Maãu soá khoâng caên lndu u C u = +∫ 2 2 1 ln2 −= +− +∫ du u a Cu a a u a Maãu soá coù caên 2du u C u = +∫ 22 ln= + + ++∫ du u u k C u k Söû duïng haèng ñaúng thöùc: 2 2 2 2 2 2 ( ) ( ) 2 2 2 2 a ax ax x b bax bx a x a a + = + − ⎡ ⎤⎛ ⎞ ⎛ ⎞+ = + −⎢ ⎥⎜ ⎟ ⎜ ⎟⎝ ⎠ ⎝ ⎠⎢ ⎥⎣ ⎦ GV: NguyÔn Thanh S¬n 2 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng 4. TÝch ph©n cña c¸c ph©n thøc h÷u tØ: 3 2 ax b A B C cx dx ex x x m x n + = + ++ + − − Giaûi daïng naøy ta coù hai caùch: − Caùch 1: Ñoàng nhaát hai veá: Cho taát caû caùc heä soá chöùa x cuøng baäc baèng nhau. − Caùch 2: Gaùn cho x nhöõng giaù trò baát kyø. Thöôøng thì ta choïn giaù trò ñoù laø nghieäm cuûa maãu soá 5. TÝch ph©n cña c¸c hµm sè l−îng gi¸c: 1. Daïng: cos , , 1). sin , cosn n1 1 sin cosaxdx= sinaxdx=- , 2). co s a a nxdx xdx ax C ax C xdx+ +∫ ∫ ∫ ∫ ∫ Phöông phaùp: n = chaün : haï baëc 2 2 1 cos 2cos 2 1 cos2sin 2 1sin cos sin 2 2 xx xx x x x +⎧ =⎪⎪ −⎪ =⎨⎪⎪ =⎪⎩ n leõ: Vieát: 2 1 2 2cos cos cos (1 sin ) cosp p pxdx x xdx x dx+ = = − Ñaët sin cosu x du x= ⇒ = dx 2. Daïng: sin cosm nu ud∫ u u a. m,n cung chaün: haï baäc. b. m,n leû (moät trong hai soá leû hay caû hai cuøng leû). Neáu m leû: Ta vieát: thay 1sin sin sinm mu u−= 1 2 2 2 2sin 1 cos (1 cos ) sinm va sin m u u u u − = − = − u Neáu m, n leû: laøm nhö treân cho soá muõ naøo beù 3. Daïng: hay ntg xdx∫ cot ng xdx∫ Chuù yù: 2 22( ) (1 ) (1 )cos 2 dx co s dxd tgx tg x dx tg x dx tgx C x x = = + ⇒ = + = +∫ ∫ Töông töï: 2 2 2(cot ) (1 ) (1 )sin 2 dx sin dxd gx cotg x dx cotg x dx cotgx C x x = − = − + ⇒ = + = − +∫ ∫ Ngoaïi tröø: sin ln cos cos (u=cosx)xdxtgxdx x C x = = +∫ ∫ Ñeå tính: ntg xdx∫ Phöông phaùp: Laøm löôïng 2( 1)tg x + xuaát hieän baèng caùch vieát: GV: NguyÔn Thanh S¬n 3 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng 2 2 2 2 2 4 2 1 2* ( 1) ( 1) ... ... ( 1) ( 1) ( 1) 1 n n n ntg x tg x tg x tg tg x tg x− − −= + − + + + + − + + n− 2 1 2 3 2 2 5 2 2 2 1* ( 1) ( 1) ... ... ( 1) ( 1) ( 1) n n n n ntg x tg x tg x tg tg x tgx tg x tgx− − − − −= + − + + + + − + + − 4. Daïng: hay 2( 1)tg x dx+∫ 2cos ndx x∫ Ta vieát: 2 2 1 2( 1) ( 1) ( 1)ntg x dx tg x tg x dx−+ = + +∫ ∫ Ñaët u = tgx 2 2( 1) ( 1)2 n (tg x+1) dx ndu tg x dx u du−= + ⇒ = + 1∫ ∫ Chuù yù: 2 22 1 1 (1 cos 2n dx, co s ntg x tg x dx) x x = + = +∫ ∫ 5. Daïng: cos m n cotg x, or sin x m n tg x dx dx x∫ ∫ Phöông phaùp: Neáu n chaün : Thay 22 2 2 21 (1 ) ; (1 ) (1 ) ( 1) cos cos mtg n n n m m n n xdxtg x tg x tgx dx tg x tgx tgx dx x x −= + ⇒ = + = + +∫ ∫ ∫ Ñaët: 22 2(1 ) m 2 n tg x du=(1+tg x)dx cos x n mu tgx dx u u du −= ⇒ ⇒ = +∫ ∫ Neáu m leû vaø n leû : 1 1 .cos cos cos m n tgx tg x tgx x x x − −= Ñaët 1cos tgx du= cosx u dx x = ⇒ Thay: 1 1 2 12 2 2 2 1 1 1 11 ( 1) . . ( 1) cos cos cos cosn tgmx cos x m m n n tgxtgx dx dx u u du x x x x − − − −= − ⇒ = − = −∫ ∫ ∫ 6. Daïng: sin cos ; sinmxsinnxdx ; cosmxcosnxdxmx nxdx∫ ∫ ∫ Aùp duïng caùc coâng thöùc bieán ñoåi: [ ] [ ] [ ] sin( ) sin( ) cos( ) s( ) cos( ) cos( ) 1 sinmxcosnx= 2 1 sinmxsinnx= 2 1 cosmxcosnx= 2 m n x m n x m n x co m n x m n x m n x • + + • − − • − + − + + GV: NguyÔn Thanh S¬n 4 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng I. TÝnh c¸c tÝch ph©n bÊt ®Þnh. Bµi 1: Dïng c¸c c«ng thøc c¬ b¶n tÝnh c¸c tÝch ph©n sau: 1/ 2 1(3x 2x )dx x + −∫ 2/ 2x 3 dxx−∫ 3/ 4 32( x )dx x −∫ 4/ 3 4 1(3 x 4 x )dxx− +∫ 5/ x x 3 2 ee (2 )dx 3 x − −∫ 6/ x 2x 3x2 .3 4 dx∫ 7/ cos (1 t )x gx dx+∫ 8/ 22(4sin x )dxcos x−∫ 9/ 2 x2cos dx 2∫ 10/ 2 2dxcos x sin x∫ Bµi 2: TÝnh c¸c tÝch ph©n sau ®©y: 1/ 2/ 10x(x 1) dx−∫ 21 2( )x 1 (x 1)−+ +∫ dx 3/ 2x x 9dx+∫ 4/ 2 24 8x dx(x 1)+∫ 5/ 3. xe dx x∫ 6/ ∫ xx dx2ln 7/ 8/ sin 7x.cos3x.dx∫ 4cos xdx∫ 9/ 3 sin x dx cos x∫ 10/ 2 2cos2x dxsin x.cos x∫ II: TÝnh c¸c tÝch ph©n x¸c ®Þnh sau: Ph−¬ng ph¸p: ( ) ( ) ( ) ( ) b a b a f x dx F x F b F a= = −∫ . 1. C¸c ph−¬ng ph¸p tÝnh tÝch ph©n. • ¸p dông b¶ng c¸c nguyªn hµm c¬ b¶n, c¸c hµm sè s¬ cÊp . • TÝnh tÝch ph©n b»ng ph−¬ng ph¸p ph©n tÝch. • TÝnh tÝch ph©n b»ng ph−¬ng ph¸p ®æi biÕn d¹ng I. • TÝnh tÝch ph©n b»ng ph−¬ng ph¸p ®æi biÕn d¹ng II. • TÝnh tÝch ph©n b»ng ph−¬ng ph¸p ®æi biÕn d¹ng III. • TÝnh tÝch ph©n b»ng ph−¬ng ph¸p tÝch ph©n tõng phÇn. • TÝnh tÝch ph©n b»ng ph−¬ng ph¸p sö dông nguyªn hµm phô. • Mét sè thñ thuËt ®æi biÕn kh¸c, tÝch ph©n chøa biÓu thøc gi¸ trÞ tuyÖt ®èi... 2. Chøng minh bÊt ®¼ng thøc tÝch ph©n GV: NguyÔn Thanh S¬n 5 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng §Ó chøng minh bÊt ®¼ng thøc tÝch ph©n , ta th−êng sö dông chñ yÕu 4 tÝnh chÊt sau: víi c¸c hµm sè f(x), g(x) liªn tôc trªn [a;b] ta cã: 1. NÕu [ ]( ) 0, ;f x x a≥ ∀ ∈ b th× ( ) 0b a f x dx ≥∫ 2. NÕu [ ]( ) ( ), ;f x g x x a b≥ ∀ ∈ th× ( ) ( )b b a a f x dx g x dx≥∫ ∫ DÊu ®¼ng thøc chi x¶y ra khi f(x) = g(x), [ ];x a b∀ ∈ 3. NÕu [ ]( ) , ;m f x M x a b≤ ≤ ∀ ∈ th× ( ) ( ) ( ) b a m b a f x dx M b a− ≤ ≤∫ − 4. ( ) ( ) . b b a a f x dx f x dx≤∫ ∫ Bµi 1: TÝnh c¸c tÝch ph©n x¸c ®Þnh sau: 1/ 2/ 2 2 3 4 0 (3x 2x 4x )dx− +∫ 1 3 2 1 ( x 3x) dx − − +∫ 3/ 4 x 4 0 (3x e )dx−∫ 4/ 2 2 3 1 x 2x dx x −∫ 5/ 0 2 1 x x 5 dx x 3− − − −∫ 6/ 5 2 dx x 1 x 2− + −∫ 7/ 1 2x x 0 e 4 dx e 2 − +∫ 8/ 32 0 4sin x dx 1 cosx π +∫ 9/ 3 0 sin x.cos3xdx π ∫ 10/ 24 2 6 2tg x 5 dx sin x π π +∫ 11/ 2 0 cos2x dx sin x cosx π −∫ 12/ 4 2 0 sin ( x)dx 4 π π −∫ Bµi 2: TÝnh c¸c tÝch ph©n cã chøa trÞ tuyÖt ®èi sau: 1/ 2 2 x 1 dx − −∫ 2/ 4 2 1 x 6x 9d− +∫ x 3/ 4 2 1 x 3x 2 d − − +∫ x 4/ 1 x 1 e 1 d − −∫ x GV: NguyÔn Thanh S¬n 6 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng 5/ 3 3 (3 x )dx − +∫ 6/ 0 2 2 x x 1 dx − +∫ 7/ 0 cosx dx π∫ 8/ 3 4 4 cos2x 1dx π π +∫ 9/ 0 cosx sinxdx π∫ 10/ 3 x 0 2 4 d−∫ x Bµi 3: Chøng minh c¸c B§T sau: 1/ 3 0 3 x 1dx≤ + ≤∫ 6 2/ 1 2 0 4 51 2 2 x dx+≤ ≤∫ 3/ 2 2 0 dx1 2 x 1 ≤ ≤+∫ 4/ 2 2 4 53 sin xdx 2 4 π π π π≤ + ≤∫ 5/ 3 4 2 4 dx 4 3 2sin x π π π π≤ ≤−∫ 2 6/ 2 2 0 3 tg x 3dx 4 2 π π π≤ + ≤∫ 7/ 2 2 sin x 2 0 e dx e 2 π ππ ≤ ≤∫ 8/ 2 2x 1 2x 1 1 e dx e dx+ ≤∫ ∫ 9/ 2 2 3 2 0 0 sin xdx sin xdx π π ≤∫ ∫ 10/ 2 2 0 0 sin 2xdx 2 sin xdx π π ≤∫ ∫ B: Ph−¬ng ph¸p ®æi biÕn: Ph−¬ng ph¸p: 1. Daïng: 1 1 ( , )n mR x x dx∫ Ñaët 1 mn mn-1 x=t dx=mnt dtmnt x= ⇒ ⇒ 2. Daïng: 1 1 ( ) , ( )n mR ax b ax b dx ⎡ ⎤+ +⎢ ⎥⎣ ⎦∫ Ñaët 1 mn mn-1mn mnt=(ax+b) ax+b=t dx= t dt a ⇒ ⇒ 3. Daïng : dxR(lnx) x∫ ñaët ln dx du = xu x= ⇒ ( )dx R(lnx) x R u du⇒ =∫ ∫ GV: NguyÔn Thanh S¬n 7 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng 4. Daïng: ñaët xR(e )dx∫ ( ) duR u u ⇒ ⇒ ⇒ =∫ ∫x x xduu=e du=e dx dx= R(e )dxu 5. Daïng : 2( , )R x ax bx c dx+ +∫ Ñöa tam thöùc 2ax bx c+ + veà daïng: hay. 2 2 2u +m ,u -m2 2 2m -u Ñoåi tích phaân thaønh 1 trong caùc daïng sau: .2 2 2 2 2 2 1). R(u, m -u )du 2). R(u, m +u )du. 3). R(u, m -u )du. ∫ ∫ ∫ Neáu döôùi daáu tích phaân coù chöùa 2 2 m -u• ñaët 2 2u=msint m -u =mcost⇒ 2 2m +u• ñaët 2 2 mu=mtgt m +u = cost ⇒ 2 2 u -m• ñaët 2 2mu= u -m =mtgt cost ⇒ 6. Daïng : 2( ) dx mx n ax bx c+ +∫ + Gaëp tích phaân naøy ñaët: 1t= mx+n Bµi 1: TÝnh c¸c tÝch ph©n sau b»ng ph−¬ng ph¸p ®æi biÕn lo¹i I 1/ 1 2 0 2x dx 1 x+∫ 2/ 4 2 0 x x 9dx+∫ 3/ 10 2 dx 5x 1−∫ 4/ 1 0 x 1 xdx−∫ 5/ 5 0 x. x 4dx+∫ 6/ 7 3 0 x dx x 1+∫ 7/ 5 3 2 0 x . x 4dx+∫ 8/ 2 2 3 3 0 3x dx 1 x+∫ 9/ 2 x 1 dx 1 e−−∫ 10/ 4 x 1 dx x.e∫ 11/ tgx 24 2 0 e dx cos x π +∫ 12/ e 1 1 3ln x dx x +∫ GV: NguyÔn Thanh S¬n 8 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng 13/ e 2 1 1 ln x dx x +∫ 14/ 6 0 1 4sin x.cos xdx π +∫ 15/ 4 2 6 1cot gx(1 )dx sin x π π +∫ 16/ 2 2 0 cos x.sin 2xdx π ∫ 17/ / 6 2 2 0 sin 2x dx 2sin x cos x π +∫ 18/ / 2 3 2 0 cos x.sin x dx 1 sin x π +∫ 19/ 8 2 3 1 dx x x 1+∫ 20/ / 3 3 0 cos x.sin x.dx π∫ Bµi 2 : TÝnh tÝch ph©n b»ng ph−¬ng ph¸p ®æi biÕn lo¹i II: 1/ 0 2 1 1 x dx − −∫ 2/ 3 2 2 3 0 1 dx (1 x )−∫ 3/ 2 2 2 1 x 4 x dx−∫ 4/ 1 2 5 dx x 4x− 7+ +∫ 5/ 2 2 0 4 dx x +∫ 6/ 4 / 3 2 3 2 x 4 dx x −∫ 7/ 1 2 2 dx x x 1 − − −∫ 8/ 6 2 2 3 dx x x 9−∫ 9/ 6 2 1 dx x x 1− + +∫ 10/ 3 2 2 1 9 3x dx x +∫ 11/ 1/ 2 1 1 xdx 1 x− + −∫ 12/ 2 2 x 2dx x 1 + −∫ 13/ 1 2 2 0 dx (x 1)(x 2)+ +∫ 14/ 3 2 0 dx x 3+∫ Bµi 3 : TÝnh tÝch ph©n c¸c hµm sè höu tØ: 1/ 2 1 dx x(2x 1)+∫ 2/ 2 2 1 dx x 6x 9− +∫ 3/ 2 1 6x 7 dx x +∫ 4/ 1 4 2 0 x dx x x 1+ +∫ GV: NguyÔn Thanh S¬n 9 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng 5/ 4 2 3 x 1 dx x 3x 2 + − +∫ 6/ 1 2 0 xdx (x 1)+∫ 7/ 6 2 2 0 sin 2xdx 2sin x cos x π +∫ 8/ 3 2 6 cosx dx sin x 5sin x 6 π π − +∫ 9/ 2 0 dx (x 1)(x 2)+ +∫ 10/ 3 2 2 1 9 3x dx x +∫ 11/ 1/ 2 2 0 dx 4x 4x 3− −∫ 12/ 4 3 2 4 2 (x x x 1)dx x 1 + − + −∫ 13/ 2 0 dx (x 1)(x 2)+ +∫ 14/ 2001 2 2001 x dx (x 1)+∫ 15/ 1/ 2 4 2 0 dx x 2x− +∫ 1 16/ 1 3 0 3dx 1 x+∫ c: Ph−¬ng ph¸p tÝch ph©n tõng phÇn: Coâng thöùc: . . . b b b a a a u dv u v v du= −∫ ∫ • Coâng thöùc cho pheùp thay moät tích phaân udv∫ phöùc taïp baèng 1 tích phaân ñôn giaûn hôn. vdu∫ • Coâng thöùc duøng khi haøm soá döôùi daáu tích phaân coù daïng: − Daïng tích soá: − Haøm soá logaric. − Haøm soá löôïng giaùc. * Daïng vôùi f(x) laø haøm nx f(x) , ln ,sin ,cos .xe x x x • Khi tính choïn: − Haøm soá phöùc taïp ñaët baèng u. − Haøm soá cos tích phaân ñöôïc cho trong baûng tích phaân thöôøng duøng laøm dv Bµi 1: Dïng ph−¬ng ph¸p tÝch ph©n tõng phÇn h·y tÝnh: GV: NguyÔn Thanh S¬n 10 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng 1/ 2/ 0 xsin xdx π∫ 1 2 2x 0 (x 1) e dx+∫ 3/ 4 2 6 x sin 2xdx π π ∫ 4/ e 2 1 (x ln x) dx∫ 5/ 4 2 0 x(2cos x 1)dx π −∫ 6/ 3 2 4 xdx sin x π π ∫ 7/ e 2 1/ e ln x dx (x 1)+∫ 8/ 4 x 1 e dx∫ 9/ 2 4 0 x cos xdx π ∫ 10/ 3 2 0 ln(x x 1)dx+ +∫ 11/ 12/ 1 2 2x 0 (x 1) .e dx+∫ 2 2 0 (x 1).sin x.dx π +∫ 13/ 2 2 1 ln(1 x) dx x +∫ 14/ 4 0 x.sin x.cos x.dx π ∫ Bµi 2: TÝnh c¸c tÝch ph©n sau: 1/ e 2 1 ln x dx x∫ 2/ 2e 1 x ln xdx∫ 3/ 2e 1 ln x dx x ⎛ ⎞⎜ ⎟⎝ ⎠∫ 4/ e 2 1 ln xdx∫ 5/ 6/ e 2 1 (x ln x) dx∫ 2 x 0 e (x sin x)dx π +∫ 7/ 8/ x 2 0 e sin ( x)dx π π∫ x 0 xe sin dx 2 π∫ 9/ x(1 sin x)e dx 1 cos x + +∫ 10/ 2 2 2 2 3 1 x dx x +∫ D: øng dông h×nh häc cña tÝch ph©n GV: NguyÔn Thanh S¬n 11 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng Bµi 1: TÝnh diÖn tÝch h×nh ph¼ng giíi h¹n bëi c¸c ®−êng (P): y = x2 - 2x + 2 ;tiÕp tuyÕn (d) cña nã t¹i ®iÓm M(3;5) vµ Oy. Bµi 2: TÝnh diÖn tÝch h×nh ph¼ng giíi h¹n bëi c¸c ®−êng (P): y = x2 + 2x vµ ®−êng th¼ng (d): y = x + 2. Bµi 3: Cho hµm sè y = 23x 5x 5 x 1 − + − (C) . TÝnh diÖn tÝch h×nh ph¼ng giíi h¹n bëi (C) ; tiÖm cËn cña nã vµ x = 2 ; x= 3. Bµi 4: Cho hµm sè y = ( )( )2x 1 x 2+ − (C) . TÝnh diÖn tÝch h×nh ph¼ng giíi h¹n bëi (C) vµ ®−êng th¼ng : x - y + 1 = 0. Bµi 5: Cho hµm sè y = 4 2x 3x 2 2 − − (C) . TÝnh diÖn tÝch h×nh ph¼ng giíi h¹n bëi (C) vµ trôc hoµnh. Bµi 6: TÝnh diÖn tÝch h×nh ph¼ng giíi h¹n bëi c¸c ®−êng (P): y2 = 4x vµ ®−êng th¼ng d : 4x - 3y - 4 = 0 . Bµi 7: TÝnh diÖn tÝch h×nh ph¼ng giíi h¹n bëi c¸c ®−êng (P): y2 + x - 5 = 0 vµ ®−êng th¼ng d : x + y - 3 = 0 . Bµi 8: TÝnh diÖn tÝch h×nh ph¼ng giíi h¹n bëi c¸c ®−êng y = 0 ; y = tgx ; y = cotgx . (0 x )≤ ≤ π Bµi 9: TÝnh diÖn tÝch h×nh ph¼ng giíi h¹n bëi c¸c ®−êng (C): x2 + y2 = 8 vµ ®−êng (P): y2 = 2x . Bµi 10: TÝnh thÓ tÝch h×nh trßn xoay do h×nh ph¼ng giíi h¹n bëi c¸c ®−êng : y = 4 x vµ y = -x + 5 quay quanh Ox. Bµi 11: Cho hµm sè y = 2x 3x x 2 3+ + + (C) . Gäi (H) lµ phÇn h×nh ph¼ng giíi h¹n bëi (C) trôc Ox vµ hai ®−êng th¼ng x = -1 , x = 0. TÝnh thÓ tÝch khèi trßn xoay t¹o thµnh khi (H) quay mét vßng xung quanh Ox. Bµi 12: Cho hµm sè y = 2x x x 1 1+ + + (C) . Gäi (H) lµ phÇn h×nh ph¼ng giíi h¹n bëi (C) trôc Ox vµ hai ®−êng th¼ng x = 0, x = 1. TÝnh thÓ tÝch khèi trßn xoay t¹o thµnh khi (H) quay mét vßng xung quanh Ox. Bµi 13: TÝnh thÓ tÝch vËt thÓ trßn xoay ®−îc t¹o thµnh do h×nh ph¼ng (D) giíi h¹n bëi : y = x , y = 2 - x vµ y = 0 khi ta quay quanh (D) quanh Oy. Bµi 14: TÝnh thÓ tÝch vËt thÓ trßn xoay ®−îc t¹o thµnh do h×nh ph¼ng (D) giíi h¹n bëi : GV: NguyÔn Thanh S¬n 12 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng y = , x = 1 vµ y = 0 ( xxe 0 x 1≤ ≤ ) khi ta quay quanh (D) quanh Ox. Bµi 15: TÝnh thÓ tÝch vËt thÓ trßn xoay ®−îc t¹o thµnh do h×nh ph¼ng (D) giíi h¹n bëi : y = sinx , y = cosx , x = 2 π vµ (0 x ) 2 π≤ ≤ khi ta quay quanh (D) quanh Ox. Bµi 16: TÝnh diÖn tÝch h×nh ph¼ng giíi h¹n bëi c¸c ®−êng sau: 1/ vµ x = -1; x = 2. 2y 0; y x 2x= = − 2/ 2y x 4x 3= − + vµ y x 3= + 3/ 2xy 4 4 = − vµ 2xy 4 2 = 4/ ln xy ;y 0;x 1 2 x = = = x e vµ = . 5/ 2y x x 1;Ox= + vµ x 1= . E. D¹ng th−êng gÆp trong c¸c k× thi §H-C§ Bµi 1: TÝnh c¸c tÝch ph©n sau: 1/ 1 3 2 0 1 x dx x +∫ 2/ ln3 3 0 ( 1) x x e dx e +∫ 3/ 0 2 3 1 ( x 1)x e x − + +∫ dx 4/ 2 6 3 5 0 1 cos .sin .cos .x x x d π −∫ x 5/ 2 3 2 5 4 dx x x +∫ 6/ 1 3 2 0 1x x dx−∫ 7/ 24 0 1 2sin 1 2sin 2 x dx x π − +∫ 8/ ln5 2 ln 2 1 x x e dx e −∫ 9/ ln5 ln 2 ( 1). 1 x x x e e dx e + −∫ 10/ − + −∫ 2 2 2 0 (3x 1) x 3x 4 dx Bµi 2: Cho hµm sè: f(x) = 3 .( 1) xa bx e x ++ T×m a, b biÕt f’(0)=-22 vµ 1 0 ( ) 5f x dx =∫ Bµi 3: TÝnh c¸c tÝch ph©n sau: GV: NguyÔn Thanh S¬n 13 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng 1/ 2 2 0 x x dx−∫ 2/ 21 3 0 . xx e dx∫ 3/ 2 1 1 ln . e x x dx x +∫ 4/ 3 1(cos )1x dxx x+ + −∫ 5/ 1 2 0 ( 1) 1 x dx x x+ +∫ 6/ 2 0 sin .sin 2 .sin 3 .x x x d π ∫ x 7/ 2 4 4 0 cos 2 (sin cos )x x x π +∫ dx 8/ 2 5 0 cos .x dx π ∫ 9/ + +∫ 3 5 3 2 0 x 2x dx x 1 10/ 1 2 3 0 (1 x ) dx−∫ Bµi 3: TÝnh c¸c tÝch ph©n sau: 1/ 2 3 3 0 ( cos sin )x x dx π −∫ 2/ 3 7 8 4 2 1 2 x dx x x+ −∫ 3/ 2 2 1 ln e x xdx∫ 4/ 3 1 lne xdx x∫ 5/ 2 0 4cos 3sin 1 4sin 3cos 5 x x dx x x π − + + +∫ 6/ 9 3 1 1x xdx−∫ 7/ 2 3 0 1 3 2 x dx x + +∫ 8/ 1 2 0 ( 2 ) xx x e dx−+∫ 9/ π +∫ 46 0 1 tg x dx cos2x 10/ − − + + +∫ 3 1 x 3 dx 3 x 1 x 3 Bµi 4: TÝnh c¸c tÝch ph©n sau: 1/ 2 0 2 2 xdx x x+ + −∫ 2/ 2 1 2 1 dx x x +∫ 3/ 1 2 0 ln(1 ) 1 x dx x + +∫ 4/ 2 0 sin sin cos x dx x x π +∫ 5 0 .sinx xdx π∫ 6/ 2 2 3 0 sin .cos .x x dx π ∫ GV: NguyÔn Thanh S¬n 14 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng 7/ 1 1 3ln .lne x x dx x +∫ 8/ 3 3 2 0 1x x dx+∫ 9/ − + +∫ 2 4 2 0 x x 1 dx x 4 10/ + −∫ 3 7 8 4 2 x dx 1 x 2x Bµi 5: TÝnh c¸c tÝch ph©n sau: 1/ 3 5 3 2 0 2 1 x x dx x + +∫ 2/ 3 3 0 1 ln .x x dx x +∫ 3/ 1 2 0 ( 1) xx e dx+∫ 4/ 3 2 4 cos 1 cos tgx dx x x π π +∫ 5/ 22 1 1 2 x dx x− −⎛ ⎞⎜ ⎟+⎝ ⎠∫ 6 20 sin 1 cos x x dx x π +∫ 7/ 1 0 1 x dx e+∫ 8/ 4 2 0 .x tg xdx π ∫ 9/ π +∫2 4 4 0 cos2x(sin x cos x)dx 10/ π ⎛ ⎞+⎜ ⎟⎝ ⎠∫ 4 0 x 1 tgxtg sin xdx 2 Bµi 6: TÝnh c¸c tÝch ph©n sau: 1/ 5 3 ( 2 2 )x x d − + − −∫ x 2/ 2 2 2 0 . ( 2) xx e dx x +∫ 3/ 4 1 2 5 4 dx x− + +∫ 4/ 1 2 2 0 (4 2 1). xx x e d− −∫ x 5/ 2 2 2 0 4x x dx−∫ 6/ 1 2 0 2 5 dx x x 2+ +∫ 7/ 2 0 sin 2 cos 1 x dx x π +∫ 8/ 1 2 0 ( 1) x dx x +∫ 9/ π +∫4 sin x 0 (tgx e cosx)dx 10/ π +∫ 2 2 20 sin x dx x sin x 2cosx.cos 2 Bµi 7: TÝnh c¸c tÝch ph©n sau: GV: NguyÔn Thanh S¬n 15 Chuyªn ®Ò: Nguyªn hµm-TÝch ph©n LuyÖn Thi §¹i Häc vµ Cao §¼ng 1/ 20042 2004 2004 0 sin sin cos x dx x x π +∫ 2/ 32 0 4sin 1 cos x dx x π +∫ 3/ 2 0 sin 2 .cos 1 cos x xdx x π +∫ 4/ 2 0 sin 2 sin 1 3cos x x dx x π + +∫ 5/ 2 sin 0 ( cos ) cos .xe x x π + dx∫ 6/ 3 2 6 cos sin 5sin 6 x dx x x π π − +∫ 7/ 2 2 1 xdx x x+ −∫ 8/ 2 0 co x dxs 7 cos 2x π +∫ 9/ ( − + + )0 2x 3 1 e x 1 dx∫ x 10/ π ∫ 23 2 0 xsin x dx sin2xcos x Bµi 8: TÝnh c¸c tÝch ph©n sau. 1/ 1 2004 1 sin .x x dx − ∫ 2/ 2 0 .sin .cos .x x x∫ dxπ 3/ 2 3 0 .cos .x x dx π∫ 4/ 42 4 4 0 cos x cos sinx x π +∫ 5/ 3 2 0 sin cos x xdx x π +∫ 6/ 1 2 0 .x tg xdx∫ 7/ CM: 02 0 2 sin sinx xdx dx x x π π >∫ 8/ CM: ∫ 4 4 0 2 sin cos dx x x π π π+∫< < 9/ π ∫ e 10/ 2 3x 0 sin5xdx π ∫ x c x 2 4 0 os dx Chóc c¸c em lµm bµi tèt ! GV: NguyÔn Thanh S¬n 16
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