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let
u=√(x-1)
2u du = dx
x=1, u=0
x=2, u=1
∫(1->2) √(x-1)/x dx
=∫(0->1) [u/(u^2+1) ] ( 2udu)
=2∫(0->1) u^2/(u^2+1) du
=2∫(0->1) [ 1- 1/(u^2+1)] du
=2[u -arctanu]|(0->1)
=2(1 -π/4)
u=√(x-1)
2u du = dx
x=1, u=0
x=2, u=1
∫(1->2) √(x-1)/x dx
=∫(0->1) [u/(u^2+1) ] ( 2udu)
=2∫(0->1) u^2/(u^2+1) du
=2∫(0->1) [ 1- 1/(u^2+1)] du
=2[u -arctanu]|(0->1)
=2(1 -π/4)
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