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Question Number 112699 by bemath last updated on 09/Sep/20

 (1) ∫ ((sin x e^(√(cos x)) )/( (√(cos x)))) dx    (2) ((1+(√(1+sin 2A)))/(1−(√(1+sin 2A))))??   (3)∫ (dx/((x+b)(x^2 +a^2 )))

(1)sinxecosxcosxdx(2)1+1+sin2A11+sin2A??(3)dx(x+b)(x2+a2)

Commented by Dwaipayan Shikari last updated on 09/Sep/20

∫((sinxe^(√(cosx)) )/( (√(cosx))))dx           cosx=t^2 , −sinx=2t(dt/dx)  −∫((2te^t )/t)dt=−2e^t +C=−2e^(√(cosx)) +C

sinxecosxcosxdxcosx=t2,sinx=2tdtdx2tettdt=2et+C=2ecosx+C

Answered by bobhans last updated on 09/Sep/20

(⧫) ∫ ((sin x e^(√(cos x)) )/( (√(cos x)))) dx=I  let u = (√(cos x)) →du = ((−sin x)/(2(√(cos x)))) dx  I = ∫ e^u (−2du) = −2e^u  + c  I=−2e^((√(cos x)) )  + c

()sinxecosxcosxdx=Iletu=cosxdu=sinx2cosxdxI=eu(2du)=2eu+cI=2ecosx+c

Answered by bobhans last updated on 09/Sep/20

(⧫⧫) ((1+(√(1+sin 2A)))/(1−(√(1+sin 2A)))) = ((1+sin A+cos A)/(1−(sin A+cos A)))   = ((1+2sin ((A/2))cos ((A/2))+2cos^2 ((A/2))−1)/(1−2sin ((A/2))cos ((A/2))−(1−2sin^2 ((A/2)))))  = ((2cos ((A/2))(sin ((A/2))+cos ((A/2))))/(2sin ((A/2))( sin ((A/2))−cos ((A/2)))))  = cot ((A/2)).((tan ((A/2))+1)/(tan ((A/2))−1))

()1+1+sin2A11+sin2A=1+sinA+cosA1(sinA+cosA)=1+2sin(A2)cos(A2)+2cos2(A2)112sin(A2)cos(A2)(12sin2(A2))=2cos(A2)(sin(A2)+cos(A2))2sin(A2)(sin(A2)cos(A2))=cot(A2).tan(A2)+1tan(A2)1

Answered by 1549442205PVT last updated on 09/Sep/20

P=((1+(√(1+sin2A)))/(1−(√(1+sin2A))))=((1+(√((sinA+cosA)^2 )))/(1−(√((sinA+cosA)))))  =((1+∣sinA+cosA∣)/(1−∣sinA+cosA∣))  i)If sinA+cosA≥0 then  P=(((1+cosA)+sinA)/((1+cosA)−sinA))=((2cos^2 (A/2)+2sin(A/2)cos(A/2))/(2cos^2 (A/2)−2sin(A/2)cos(A/2)))  =((2cos(A/2)(cos(A/2)+sin(A/2)))/(2cos(A/2)(cos(A/2)−sin(A/2))))=((cos(A/2)+sin(A/2))/(cos(A/2)−sin(A/2)))  =(((√2) cos((𝛑/4)−(A/2)))/( (√2) cos((𝛑/4)+(A/2))))=((cos((𝛑/4)−(A/2)))/(cos((𝛑/4)+(A/2))))   ii)If sinA+cosA<0 then .Similarly,  we get P=((1−sinA−cosA)/(1+sinA+cosA))  =((2sin^2 (A/2)−2sin(A/2)cos(A/2))/(2cos^2 (A/2)+2sin(A/2)cos(A/2)))=((2sin(A/2)(sin(A/2)−cos(A/2)))/(2cos(A/2)(cos(A/2)+sin(A/2))))  =tan(A/2)×((sin((𝛑/4)−(A/2)))/(sin((𝛑/4)+(A/2))))   3)Find ∫ (dx/((x+b)(x^2 +a^2 )))  F=∫ (dx/((x+b)(x^2 +a^2 )))=∫(dx/((a^2 +b^2 )(x+b)))  −∫ ((x−b)/((a^2 +b^2 )(x^2 +a^2 )))dx  =(1/(a^2 +b^2 ))ln∣x+b∣−(1/(a^2 +b^2 ))×(1/(2a))tan^(−1) ((x/a))

P=1+1+sin2A11+sin2A=1+(sinA+cosA)21(sinA+cosA)=1+sinA+cosA1sinA+cosAi)IfsinA+cosA0thenP=(1+cosA)+sinA(1+cosA)sinA=2cos2A2+2sinA2cosA22cos2A22sinA2cosA2=2cosA2(cosA2+sinA2)2cosA2(cosA2sinA2)=cosA2+sinA2cosA2sinA2=2cos(π4A2)2cos(π4+A2)=cos(π4A2)cos(π4+A2)ii)IfsinA+cosA<0then.Similarly,wegetP=1sinAcosA1+sinA+cosA=2sin2A22sinA2cosA22cos2A2+2sinA2cosA2=2sinA2(sinA2cosA2)2cosA2(cosA2+sinA2)=tanA2×sin(π4A2)sin(π4+A2)3)Finddx(x+b)(x2+a2)F=dx(x+b)(x2+a2)=dx(a2+b2)(x+b)xb(a2+b2)(x2+a2)dx=1a2+b2lnx+b1a2+b2×12atan1(xa)

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