Question Number 94245 by mhmd last updated on 17/May/20

Answered by Ar Brandon last updated on 17/May/20
![Q1\ ∫_0 ^1 ∫_0 ^1 (1/( (√(1+x^2 −y^2 ))))dydx=∫_0 ^1 (1/( (√(1+x^2 ))))∫_0 ^1 (1/( (√(1−((y/( (√(1+x^2 )))))^2 ))))dydx =∫_0 ^1 [sin^(−1) ((y/( (√(1+x^2 )))))]_0 ^1 dx=∫_0 ^1 sin^(−1) ((1/( (√(1+x^2 )))))dx u=sin^(−1) ((1/( (√(1+x^2 )))))⇒du=−2x∙(1/2)∙(1/((1+x^2 )^(3/2) ))∙(1/( (√(1−(1/(1+x^2 )))))) =−(x/((1+x^2 )^(3/2) ))∙(1/( (√(x^2 /(1+x^2 )))))=−(x/((1+x^2 )^(3/2) ))∙((√(1+x^2 ))/x)=−(1/(1+x^2 ))dx dv=dx⇒v=x ∫_0 ^1 sin^(−1) ((1/( (√(1+x^2 )))))dx=[xsin^(−1) ((1/( (√(1+x^2 )))))]_0 ^1 +∫_0 ^1 (x/(1+x^2 ))dx =(π/4)+[(1/2)ln(1+x^2 )]_0 ^1 =(π/4)+(1/2)ln(2)](https://www.tinkutara.com/question/Q94253.png)
Commented by mhmd last updated on 17/May/20

Commented by Ar Brandon last updated on 17/May/20
��You're welcome. I realised the previous post was deleted and that's why I decided to post it here.
Commented by mhmd last updated on 17/May/20

Commented by Tinku Tara last updated on 17/May/20

Commented by mhmd last updated on 17/May/20

Commented by Ar Brandon last updated on 17/May/20
I think it was deleted before I commented. Because after solving I tried to send but to no avail so I gave up. But my solution was saved. And when I wanted to answer the next question it just appeared so I sent it.