sqrt(1+sinx)=sqrt((sin(x/2)+cos(x/2))^2)=|sin(x/2)+cos(x/2)|=(sin(x/2)+cos(x/2) на [π/2;π}
Данный интеграл равен интегралу
∫_(π/2) ^(π)(sin(x/2)+cos(x/2))dx=2∫_(π/2) ^(π)sin(x/2) d(x/2)+2∫_(π/2) ^(π)cos(x/2)d(x/2)=
=2(-cos(x/2))|_(π/2) ^(π)+2(sin(x/2))_(π/2) ^(π)=
=-2cos(π/2)+2cos(π/4)+2sin(π/2)-2sin(π/4)=
=2*0+2*(sqrt(2)/2)+2*1-2*(sqrt(2)/2)=2