∴f′(x)=(ex)′(sinx-cosx)+ex(sinx-cosx)′=2exsinx,
∵x∈(2kπ,2kπ+π)时,f′(x)>0,x∈(2kπ+π,2kπ+2π)时,f′(x)<0,
∴x∈(2kπ,2kπ+π)时原函数递增,x∈(2kπ+π,2kπ+2π)时,函数f(x)=ex(sinx-cosx)递减,
故当x=2kπ+π时,f(x)取极大值,
其极大值为f(2kπ+π)=e2kπ+π[sin(2kπ+π)-cos(2kπ+π)]
=e2kπ+π×(0-(-1))
=e2kπ+π,
又0≤x≤2014π,
∴函数f(x)的各极大值之和
S=eπ+e3π+e5π+…+e2013π
=
| eπ(1−(e2π)1007) |
| 1−e2π |
=
| eπ(1−e2014π) |
| 1−e2π |
故选:B.
