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x-1-x-1-x-1-x-1-dx-




Question Number 65015 by aliesam last updated on 24/Jul/19
∫(((√(x+1)) − (√(x−1)))/( (√(x+1)) + (√(x−1)))) dx
x+1x1x+1+x1dx
Commented by mathmax by abdo last updated on 24/Jul/19
let I =∫  (((√(x+1))−(√(x−1)))/( (√(x+1))+(√(x−1))))dx ⇒I =∫ ((((√(x+1))−(√(x−1)))^2 )/(x+1−x+1))dx  =(1/2) ∫ (x+1−2(√(x^2 −1)) +x−1)dx  =(1/2) ∫ (2x−2(√(x^2 −1)))dx =∫ xdx−∫(√(x^2 −1))dx  =(x^2 /2) −∫ (√(x^2 −1))dx  chang.x=cht give  ∫ (√(x^2 −1))dx =∫  sht sht dt =∫ sh^2 t dt =∫((ch(2t)−1)/2)dt  =(1/4)sh(2t) −(t/2) =(1/2)sht cht −(t/2)  but t =argch(x)=ln(x+(√(x^2 −1)))  ⇒∫(√(x^2 −1))dx =(1/2)x(√(x^2 −1))−(1/2)ln(x+(√(x^2 −1))) ⇒  I =(x^2 /2) +(1/2)ln(x+(√(x^2 −1)))−(1/2)x(√(x^2 −1))  +C .
letI=x+1x1x+1+x1dxI=(x+1x1)2x+1x+1dx=12(x+12x21+x1)dx=12(2x2x21)dx=xdxx21dx=x22x21dxchang.x=chtgivex21dx=shtshtdt=sh2tdt=ch(2t)12dt=14sh(2t)t2=12shtchtt2butt=argch(x)=ln(x+x21)x21dx=12xx2112ln(x+x21)I=x22+12ln(x+x21)12xx21+C.
Commented by aliesam last updated on 24/Jul/19
thank you sir
thankyousir
Commented by mathmax by abdo last updated on 24/Jul/19
you are welcome.
youarewelcome.
Answered by Tanmay chaudhury last updated on 24/Jul/19
∫((x+1−2(√(x^2 −1)) +x−1)/(x+1−x+1))dx  ∫x−(√(x^2 −1)) dx  (x^2 /2)−(((x(√(x^2 −1)))/2)−(1/2)ln(x+(√(x^2 −1)) )+c
x+12x21+x1x+1x+1dxxx21dxx22(xx21212ln(x+x21)+c
Commented by aliesam last updated on 24/Jul/19
thank you sir
thankyousir
Commented by Tanmay chaudhury last updated on 24/Jul/19
most welcome sir
mostwelcomesir

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