Y=lncosx-cose 求：Y

y=lncosx-cosx
y'=-sinx/cosx+sinx
y=x^3lnx y'=3x^2lnx +x^2
y''=6xlnx+3x+2x=6xlnx+5x
f(x)=(1+cosx)x
f'(x)=1-xsinx+cosx