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Question Number 34827 by Cheyboy last updated on 11/May/18

Find ∫ Sin^6 x dx

FindSin6xdx

Commented by rahul 19 last updated on 11/May/18

sir how   sin^6 xdx= (((e^(ix) −e^(−ix) )/(2i)))^6 ?

sirhowsin6xdx=(eixeix2i)6?

Commented by Cheyboy last updated on 11/May/18

Sir i dnt understand ur method  plz be simplistic

Siridntunderstandurmethodplzbesimplistic

Commented by abdo mathsup 649 cc last updated on 11/May/18

i have given the key becsuse  ∫  e^(i(2k−6)x) dx = (1/(2k−6)) e^(i(2k−6)x)  +λ  =(1/(2k−6))( cos(3k−6)x +isin(3k−6)x) +λ.....

ihavegiventhekeybecsuseei(2k6)xdx=12k6ei(2k6)x+λ=12k6(cos(3k6)x+isin(3k6)x)+λ.....

Commented by math khazana by abdo last updated on 11/May/18

another method  (linearization)  ∫ sin^6 xdx  = ∫   (  ((e^(ix)    −e^(−ix) )/(2i)))^6 dx  = (1/((2i)^6 ))  ∫   Σ_(k=0) ^6  C_6 ^k     e^(ikx)   e^(−i(6−k)x)  dx  = (1/((2i)^6 ))  Σ_(k=0) ^6  C_6 ^k      ∫   e^(i(2k−6)x) dx ....

anothermethod(linearization)sin6xdx=(eixeix2i)6dx=1(2i)6k=06C6keikxei(6k)xdx=1(2i)6k=06C6kei(2k6)xdx....

Commented by abdo mathsup 649 cc last updated on 11/May/18

its a formula   ((e^(ix)   −e^(−ix) )/(2i)) =((2iIm(e^(ix) ))/(2i))  = sinx .

itsaformulaeixeix2i=2iIm(eix)2i=sinx.

Answered by tanmay.chaudhury50@gmail.com last updated on 11/May/18

=∫(((1−cos2x)^3 )/2^3 )  (1/8)∫((1−3cos2x+3cos^2 2x−cos^3 2x)/)  (1/8)∫dx−(3/8)∫cos2x dx+(3/8)∫(((1+cos4x))/2)−(1/8)∫cos^3 2x  =(x/8)−(3/(16))sin2x+(3/(16))(x+((sin4x)/4))−(1/8)∫((cos6x+3cos2x)/4)  =do−(1/(32))∫cos6x+3cos2x  =do−(1/(32)) ×((sin6x)/6)−(3/(32))×((sin2x)/2)  =(x/8)−(3/(16))sin2x+(3/(16))(x+((sin4x)/4))−(1/(32))((sin6x)/6)−(3/(64))×                                    sin2x  x((1/8)+(3/(16)))−sin2x((3/(16))+(3/(64)))+sin4x((3/(64)))  −sin6x((1/(192)))  =x((5/(16)))−sin2x(((15)/(64)))+sin4x((3/(64)))−(1/(192))sin6x  =(5/(16))x−((15)/(64))sin2x+(3/(64))sin4x−(1/(192))sin6x

=(1cos2x)3231813cos2x+3cos22xcos32x18dx38cos2xdx+38(1+cos4x)218cos32x=x8316sin2x+316(x+sin4x4)18cos6x+3cos2x4=do132cos6x+3cos2x=do132×sin6x6332×sin2x2=x8316sin2x+316(x+sin4x4)132sin6x6364×sin2xx(18+316)sin2x(316+364)+sin4x(364)sin6x(1192)=x(516)sin2x(1564)+sin4x(364)1192sin6x=516x1564sin2x+364sin4x1192sin6x

Commented by Cheyboy last updated on 11/May/18

complete it plzz

completeitplzz

Commented by tanmay.chaudhury50@gmail.com last updated on 11/May/18

pls go throuvh it

plsgothrouvhit

Commented by Cheyboy last updated on 11/May/18

Thank you

Thankyou

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