∫0π11+sinxdx=
1
2
–1
–2
∫0π11+sinxdx=2∫0π/211+sinxdx=2∫0π/21−sinxcos2xdx=2∫0π/2(sec2x−secxtanx)dx
=2[tanx−secx]0π/2=−2[1−sinxcosx]0π/2=−2[cosx1+sinx]0π/2=−2[0−1]=2