下列诗句与其所描述的生产活动对应错误的是:
B
暂无解析
设f(x,y)具有一阶偏导数,且对任意的(x,y),
Ihavebeenstudyinghereforfouryears,bynextsummerI________.
Hefellasleepimmediatelylastnight;hemust________(be)verytired.
设f(x,y)在点(0,0)附近有定义,且,则
设函数y=e^x+1,则y''=()