xcosx/(1+sinx^2)这项也是奇函数,所以是0
只剩下cosx/(1+sinx^2)了
积分(-π/2到π/2) [ cosx/(1+sinx^2) ]dx
=积分(-π/2到π/2) [ 1/(1+sinx^2) ]dsinx
=arctan(sinx) | (-π/2到π/2)
=2arctan1
=π/2
xcosx/(1+sinx^2)这项也是奇函数,所以是0
只剩下cosx/(1+sinx^2)了
积分(-π/2到π/2) [ cosx/(1+sinx^2) ]dx
=积分(-π/2到π/2) [ 1/(1+sinx^2) ]dsinx
=arctan(sinx) | (-π/2到π/2)
=2arctan1
=π/2