Question

(y=x^2lnxcosx）大学高数求导!

Answer 1

先把前两项或者后两项放一起 ,

y'=(x^2)'lnxcosx+x^2(lnxcosx)'

=2xlnxcosx+x^2(lnx'cosx+lnxcosx')

=2xlnxcosx+x^2(1/xcosx-lnxsinx)

=2*x*ln(x)*cos(x)+x*cos(x)-x^2*ln(x)*sin(x)