cos(xy),

函数求导
上的五个关键点的坐标为(0,0) (π,0) (2π,0)(2)y=cosx的图象在[0
fy=cos(x y)-xe^(xy) ∴y'=-fx/fy=-[cos(x y)-ye^(xy)]/[cos(x y)-xe
【cos正片】宝可梦xy瑟蕾娜cos,小姐姐也太好看了吧!
z'x=ycos(xy) z'y=xcos(xy) dz=z'xdx z'ydy 在点(0