f′(x)=xsec2x+2xcosx+tanx−x2sinx 16) First derivative of y=x(lnx)cosxdydx=cosx⋅(lnx+1)−x(lnx)sinx 18) Second derivative of y=4x+x2sinx \(\dfrac...f′(x)=xsec2x+2xcosx+tanx−x2sinx 16) First derivative of y=x(lnx)cosxdydx=cosx⋅(lnx+1)−x(lnx)sinx 18) Second derivative of y=4x+x2sinxd2ydx2=4x(ln4)2+2sinx+4xcosx−x2sinx In exercises 19 and 20, find the equation of the tangent line to the following equations at the specified point. 20) y=x+ex−1x at x=1