A.
2 cos ( x 2 − y 2 ) − 4 x 2 sin ( x 2 − y 2 ) " role="presentation" style="display: inline-table; line-height: 0; font-size: 19.52px; overflow-wrap: normal; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; color: rgb(0, 0, 0); font-family: "Microsoft YaHei"; position: relative;" > 2 cos ( x 2 − y 2 ) − 4 x 2 sin ( x 2 − y 2 ) 2cos(x2−y2)−4x2sin(x2−y2)
B.
sin ( x 2 − y 2 ) " role="presentation" style="display: inline-table; line-height: 0; font-size: 19.52px; overflow-wrap: normal; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; color: rgb(0, 0, 0); font-family: "Microsoft YaHei"; position: relative;" > sin ( x 2 − y 2 ) sin(x2−y2)
C.
− 4 x 2 sin ( x 2 − y 2 )
D.
− sin ( x 2 − y 2 ) " role="presentation" style="display: inline-table; line-height: 0; font-size: 19.52px; overflow-wrap: normal; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; color: rgb(0, 0, 0); font-family: "Microsoft YaHei"; position: relative;" > − sin ( x 2 − y 2 ) −sin(x2−y2)